storm water management &modelling

STORM WATER MANAGEMENT & MODELLING

Summer Internship Programme 2010

INDIAN SPACE RESEARCH ORGANIZATION

akshay anand Faculty of Geomatics and Space Application

CEPT UNIVERSITY

Acknowledgements I would like to share my deep gratitude to my guide Mr. Gaurav Jain, for having faith in me and sharing his in-depth knowledge and consistent guidance throughout my internship. Also thanking my guide for constant valuable inputs and discussions which I take it ahead in academics as well as in professional life. I am grateful to Prof. Anjana Vyas, Dean, Faculty of Geomatics and Space Applications for giving me opportunity to undergo training in a prestigious institution as ISRO. Thanks to Dr. S.K. Pathan, Head, GIDD/GTDG/RESA for allowing me to work on a challenging and research oriented topic with encouragements and also for extending his knowledge and guidance with valuable insights and critique. I also wish to thanks the technical staff and library for extending their co-operation throughout my internship at SAC campus.

INDIAN SPACE RESEARCH ORGANIZATION Space Application Center – Ahmedabad

Dr. Vikram Sarabhai Space activities in the country started during early 1960s with the scientific investigation of upper atmosphere and ionosphere over the magnetic equator that passes over Thumba near Thiruvananthapuram using small sounding rockets. Realizing the immense potential of space technology for national development, Dr. Vikram Sarabhai, the visionary leader envisioned that this powerful technology could play a meaningful role in national development and solving the problems of common man. Thus, Indian Space programme born in the church beginning, space activities in the country, concentrated on achieving self reliance and developing capability to build and launch communication satellites for television broadcast, telecommunications and meteorological applications; remote sensing satellites for management of natural resources. The objective of ISRO is to develop space technology and its application to various national tasks. ISRO has established two major space systems, INSAT for communication, television broadcasting and meteorological services, and Indian Remote Sensing Satellites (IRS) system for resources monitoring and management. ISRO has developed two satellite launch vehicles, PSLV and GSLV, to place INSAT and IRS satellites in the required orbits Accordingly, Indian Space Research Organisation (ISRO) has successfully operationalised two major satellite systems namely Indian National Satellites (INSAT) for communication services and Indian Remote Sensing (IRS) satellites for management of natural resources; also, Polar Satellite Launch Vehicle (PSLV) for launching IRS type of satellites and Geostationary Satellite Launch Vehicle (GSLV) for launching INSAT type of satellites. The Space Commission formulates the policies and oversees the implementation of the Indian space programme to promote the development and application of space science and technology for the socio-economic benefit of the country. DOS implements these programmes through, mainly Indian Space Research Organisation (ISRO), Physical Research Laboratory (PRL), National Atmospheric Research Laboratory (NARL), North Eastern-Space Applications Centre (NE-SAC) and Semi-Conductor Laboratory (SCL).

Storm Water Management & Modelling - a study of Paldi Catchment area 7/297/291

Akshay Anand Faculty of Geomatics and Space Application, CEPT University Internship Programme: Indian Space Research Organization, Ahmedabad

DECLARATION This is to declare that the work carried out by Akshay Rameshchandra Anand during the internship programme at Space Application Center, Ahmedabad is strictly for academic research purpose only and is done under close guidance by his respective guide and is to the notice of the respective Head of academic institution – CEPT University. Akshay Rameshchandra Anand has successfully carried out his internship by working on the project given by his Guide and Head of the Division.

Guide Shri. Gaurav Jain ‘Scientist/Engr SE’ GIDD/GTDG/RESA

Head Dr. S.K Pathan ‘Scientist/Engr H’ GIDD/GTDG/RESA



Abbrevations API5 Antecedent Precipitation Index (over previous 5 days) BOD Biochemical Oxygen Demand CWC Central Water Commission COD Chemical Oxygen Demand CWI Catchment Wetness Index from FSR DO Dissolved Oxygen EPA Environmental Protection Agency FEH Flood Estimation Handbook (Centre for Ecology and Hydrology (CEH), 1999) FSR Flood Studies Report (Institute of Hydrology, 1975) FSSR Flood Studies Supplementary Reports (Institute of Hydrology, 1985) IDF Intensity – Depth – Frequency (relationship) IF Effective Impervious Area Factor M560 The 5 year 60 minute depth of rainfall NAPI New Antecedent Precipitation Index NERC Natural Environment Research Council NIH National Institute of Hydrology PF Porosity Fraction (soil storage depth) PIMP Percentage Impermeable proportion of a catchment or development contributing to runoff– see PR equation PR Percentage Runoff QBAR An FSR term denoting the Mean Annual Flood flow rate for a river. This approximates to a return period of 2.3years RDII Rainfall-Dependent Infilteration/Inflow SAAR Standard Average Annual Rainfall assessed over the period of years SAT Soil Aquifer Treatment SMD Soil Moisture Deficit SOIL Soil type classification used by Institute of Hydrology, FSR, 1975 and the HR Wallingford and Institute of Hydrology, Wallingford Procedure, 1981 SPM Suspended Particulate Matter STP Sewage Treatment Plant SPR Standard Percentage Runoff. Used in FSR and FEH equations SUDS Sustainable Urban Drainage Systems SWMM Storm Water Management and Modeling TSR T ime Series Rainfall TOC Total Organic Carbon TSS Total Suspended Solid UCWI Urban Catchment Wetness Index – describes the wetness of the catchment, usually calculated for the start of a rainfall event WRAP Winter Rainfall Acceptance Potential (used by the HR Wallingford and Institute of Hydrology, Wallingford Procedure, 1981) WR Wind Rose



Project Summary

The hazards and disaster are not area specific and their vulnerability is high in urban areas where the density of population is high. The cities in India are expanding in physical, economical and social dimensions. Thus so often these cities expose the exhaustion and limitations in accommodating services to the settlement. Lack of infrastructure amenities such as drainage, water supply, sanitation, transportation and social services lead to the decay of urban environments. The problems arising due to occurrence of some natural events and hazards multiply in the defined environment. Thus a lack of proper physical planning and the infrastructure in urban cities aggravate the severity of natural hazards and causes catastrophic loss to the human life and property. Floods can be - river-in flood, storm runoff flood, and cyclonic flood to the meteorological flood. However on average these floods have problems with variations in magnitude of severity and its impact. So, whether our current urban scenario that struggles to cop up with current issues can control such sudden natural hazards is the question of inquiry. The study is based on the rainfall runoff modeling and estimation of the selected subcatchment area of Paldi, which is on the lower gradient of the Ahmedabad city and prone to flooding in heavy rain falls. This study would particularly concentrate on urban storm water floods, which may not have severe impact but could be a threat to the future sustainability of the city. There are many examples of the city experiencing flash floods, which have eventually resulted large-scale losses to human life and property. Therefore it is highly essential to control the storm water floods in urban areas to prevent water logging, and thus modeling the existing scenario and creating multiple hour based storm events we can check whether the current capacity and infrastructure is sufficient enough to control the actual storm.



Contents…. Acknowledgements About the institution Abbreviation Chapter 1 Introduction

1.1 State of the Art 1.2 Objective 1.3 Data and Platforms 1.4 Methodology 1.5 Framework of Analysis

Chapter 2

Literature Review 2.1 Urban Hydrology 2.2 Characteristics of Models 2.3 Chronology of Hydrological Modeling Chapter 3 Study area – Paldi catchment area, Ahmedabad city

3.1 Introduction to Study area 3.2 Location and Climate 3.3 Drainage System 3.4 Topography 3.5 Rainfall and Climate

Chapter 4 Storm water Management and Modeling 4.1 Stormwater Management and Modeling 4.2 Modeling Capabilities

4.3 Hydrologic Analysis of catchment area Analysis of Simulation Results Chapter 5 Low Impact Development 5.1 Bioretention 5.2 Bioswales 5.3Tree box filters 5.4 Permeable Pavements Project Simulation Report and Summary Annexure Glossary References



Introduction 1.1 State of the Art Urban hydrology is a specific knowledge of hydrology applied in areas with very high concentration of human activities which deal with natural process. The continuous growth of population and massive development will affect the physical characteristics of an area and change the hydrological practice. A notable aspect of urbanization is the increase of impervious surfaces, which include paved streets, roads, parking lots and roofs. High impervious surfaces are the common cause for high runoff volumes as the soil infiltration capacity decreases. Thus, the drainage system for urban areas is relatively different from natural catchments whereby it is designated specifically to remove the runoff as fast as possible so that flooding can be prevented and the negative influence on transportation is minimized. Flooding phenomena frequently occur in some cities during rainy period, which is often caused from the even terrain of the cities, the lower design standard of the drainage systems, and conduits blocked up by construction waste during urban development period. It is an important task to forecast flooding area during periods of storm, analyze potential after effect of flood disaster and decide counter measures of flood control for the cities at present. The hydrologic and hydraulic characteristics in an urban basin are far more complex than that in a natural watershed. A variety of phenomenon is likely to occur in some urban drainage systems that involve gravity flow, pressure flow, circumfluence flow, backward flow and surcharge flow. Sometimes, flooding occur in urban basins during rainy period. These methods in common used to design urban drainage system are not suitable for analyses of surcharge systems or simulation of flooding processes in cities. For example, rational formula method, isochrones method or unit hydrograph method is only used to compute flood peak discharge and flow hydrograph in design conditions for urban basins. Since 1970s, a number of mathematical models for urban storm water were set up of which some can well simulate flow hydrograph of urban drainage systems. The storm water management model (SWMM), one of the most excellent models, was developed by the Environmental Protection Agency of US in 1971. SWMM can simulate gravity flow, pressure flow, circumfluence flow, backwater flow of storm drainage systems in design conditions, and is widely used throughout the world for planning, analysis and design related to storm water runoff, combined sewers, sanitary sewers, and other drainage systems in urban areas. But little models can simulate storm water flooding of urban basins during rainy period, which do not satisfy the demand of flood prevention and the disaster reduction for the cities. Based on the analyses of hydraulic characteristics of urban drainage systems the numerical simulation techniques are used to set up a mathematical model that can especially simulate and forecast flooding processes during rainy period, which provide important information flood prevention and disaster reduction of the cities.

Storm Water Management & Modelling - a study of Paldi Catchment area 1


1.2 Objectives To address the issue of storm water with rainfall and runoff processes in urban areas.

The key objectives of this study are as follows:

To establish a reliable relationship between rainfall and runoff and obtain estimate for impervious of the catchment.

To estimate the impervious surface by using satellite images and digital maps and compare the results with values obtained from the rainfall-runoff correlation.

To carryout modelling of selected area in Ahmedabad with EPA-SWMM environment and study simulation results.

1.3 Data and Platforms used.

Data Remote Sensing Data

- Cartosat 1a and 2a

Indian Meteorological Data - Climatological tables of 2009

Ahmedabad Municipal Corporation - Drainage system of the study area

Platforms Environmental Protection Agency’s – SWMM 5.0

Lakes Environment - Wind Rose Plot

ESRI – Arc Info

ERDAS imagine



1.4 Methodology



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1.5 Framework of Analysis



Literature Review 2.1 Urban Hydrology Urban Hydrology is defined as the interdisciplinary science of water and its interrelationship with urban man (Jones 1971). In other words, urban hydrology is a special case of hydrology applied to cities i.e areas with high level of human interference with natural processes. Its a relativelly upcoming field and has developed fast since 1960s. The begennings of urban hydrology can be traced to the time shortly after use of automobiles became the major means of transportation. Roads were paved to facilitate travel, allowing the growth of the suburbs where the commuter escaped the congestion of inner city life. Growth of urban areas brought significant changes in physical properties of land surface increasing integrated vulnerability of inhabitants.The result was the rapid creation of large impervious areas, producing noticeable drainage problems. Urban Hydrological System The hydrological cycle describes different hydrological processes, various paths by which water precipitated onto the land surface finds its way to the ocean and evaporation gives moisture, thus completing the cycle. Different components of hydrologic cycle are evaporation, precipitation, infilteration, runoff, streamflow and groundwater. However, due to the effect of the urban environment, the hydrological processes are more complicated. Some of the differences are (Hall 1984) Natural drainage systems are altered and supplemented by sewerage systems. Effects of flooding are mitigated by different schemes. Wastewater disposal scheme exists. Water is supplied from remote location.

Importance is the relative location of an urban center in the river basin of which it is a part, as well as the degree and character of its hydrological overlap with other urban centers, and thier distance from a large lake or an ocean. Because early commerce utilised waterways for transportation, th great majority of metropolises are located on or near major water bodies. Hence, they frequently occupy low-lying ground, and tend to be located near estuaries of major streams or the junction with the tributaries, or along a coast. The advantages of superior water transport, water supply and water-assimilation capacity through self purification afforded by many of these locations have since been partly offset by increases in flooding damages and pollution that have accompained more intensive urbanisation. An urban drainage storm water model can be divided into four individual parts: the precipitation input, the hydrological surface processes, the hydrodynamics of the surface flow, and finally the hydrodynamics of the pipe flow. Hydrological Problems, Challenges and Issues of Urban Areas The following are the major hydrological problems of urban areas : Supply of clean pure drinking water. Provision of adequate flows for the disposal of waterborne wastes. Magnitude of the per capitia domestic consumption of water. Requirement of water for industrial processes, recreation, and amenity purpose. Storm water management. Heat production in urban area.



Sewerage system. Water quality. Recycling of the waste water. Sources of urban pollutants Lowering of ground water table

Hydrological Issues The major hydrological issues which are as follows: Disruption of the natural hydrological cycle due to reduction of infiltration and

groundwater recharge, increase in surface runoff and flooding. Decline in water levels and possible land subsidence due to groundwater mining Determination of surface and groundwater quality. Increase pollutant loads from runoff discharges and sewage outfalls of poor quality. Leakage to groundwater from old and poorly maintained sewers. Extensive soil and groundwater contamination from industrial leakage, or spills of

hazardous chemicals or poorly planned solid and liquid waste disposal practices. Increased artificial surface water infiltration and recharge from source control device

leading to poor groundwater quality. Reduction in ecological habitat and species diversity of the receiving water body. Need for integrated land use and catchment planning.

Hydrological Challenges Delivery of drinking water supply for growing cities Water for sanitation versus sanitation without water Recycling of wastewater nutrients Wastewater irrigation Storm water management and modelling and drainage Rainwater harvesting Artificial recharge of depleted aquifers Urban agriculture Recovery of resources present in solid and fluid wastes Paradigm shift from water disposal and treatment to conservation and recycling of

resources. New programs like dry sanitation

A state of the art study of urban development on flood discharges revealed areas of needed research. It is indicated that too few data have been collected to describe the effect of urban and suburban development on flood runoff. It was recognised that, in general, the volume of flood runoff is increased in impervious areas which are the consequence of urban development. It was agreed that the acceleration and concentration of flood water by runoff from impervious areas, and by the concentration of storm sewers, gutters, catch basins, and channel improvements contributed most to the increased flows experienced in urban environments. Disclaimers or qualifications to further generalization were stipulated because of the throttling effect of various encroachments, e.g, loss of natural storage from flood plain development and the wide variety drainage and flood mitigation development patterns commonly encountered. Examination of available data and of the results of various studies indicates that the most dramatic hydrologic impact of urban development, and the one that has received the most



attention, is that on peak flows in streams and storm drains. Comparative studies of urban versus rural drainage basins indicate that as the relative magnitude of flood peaks increases, the ratio of urban peak rate declines, the effect of urbanization being more pronounced for the more frequent occurrences. The larger an urban complex the greater the hydrologic region that may be impacted in the acquisition of its water supply. Base flows of streams can be raised by wastewater effluents that originated as imported water or can be diminished as a consequence of recharge denied by imperviousness or via surface water diversions. The increased volume of direct storm runoff resulting from urbanization can reduce low flows because less precipitation is available for soil moisture replenishment and groundwater storage. However, it is evident that the cumulative effects of urbanization on a drainage basin can be either a decrease or an increase in the low flows of streams. Interbasin diversions of water further complicate hydrologic patterns. Runoff. Off the precipitation upon a catchment area, some runs off immediately to appear in streams as storm or flood flow; some evaporates from land and water surfaces; some little evaporation; some through, interception caught on leaves of vegetation and evaporates; and some termed as infiltration, seeps into the ground. Of the infiltration a part is taken up by vegetation and transpired through the leaves; some percolates through the soil to emerge again to form springs and streams which make up the dry whether flow; a part is held by capillarity of the soil; another part is held in the soil particles by molecular action; while a small portion may penetrate into deep porous underground strata and be lost so far as the catchment area is concerned. The last three factors usually are of little or no consequence so far as the runoff is concerned. The difference between the total flow of a steam, as indicated by gagings, and the rainfall of its watershed will be the water lost by evaporation and otherwise. Factors which affect Runoff. The total runoff from a drainage area is made up of the direct runoff and flows from ground water sources. Direct runoff is the water that has not passed through the soil since precipitation. The ground water runoff is that which has been a part the ground water. Temperature and its variation on the watershed area will affect evaporation. The amount and type of vegetal cover affect infiltration and the loss of water by transpiration. The topography of the drainage area, its smoothness or roughness and gentle or steep slopes, affects the speed of concentration of the direct runoff and thereby causes high or low runoff rates. Short concentration periods may cause flash floods. Slower concentration allow more infiltration and greater evaporation. Natural storage in surface ponds and lakes contributes to slower concentration and greater evaporation. Runoff Modelling. The first step in preparing a hydrologic model is to properly delineate the drainage basin and the subcatchments within that basin. Once these subcatchments have been delineated, hydrologic parameters are assigned to each of the basins. The RUNOFF model applies a rainfall pattern to each of these small basins and calculates a time-series of stormwater runoff flows. These flows are “loaded” into the hydraulic model that routes the flows downstream. Rainfall-Intensity-Duration-Frequency- Relationships. The rate at which rain falls over an area and its duration are of importance for several reasons. A duration equal to the time of concentration, or the time required for the water to run from the farthest part of the catchment basin to the point in question, is critical since the shorter the duration of a rainfall the greater may be its average intensity. The greatest intensity to be expected for the critical duration therefore will produce the greatest runoff.



The Hydrograph The hydrograph is a graphical chronological representation of the flow of a stream. Usually the ordinates are expressed in daily discharge is one of the units of annual hydrographs. A base flow or runoff will be noted.

2.2 Model Classification Deterministic - Based on assumption that process can be defined in physical terms without a random concept. Stochastic - Based on assumption that FLOW, at any time is a function of antecedent flows and a random component. Conceptual - Conceptual understanding of Hydrological cycle with empirically determined functions. Theoretical - Series of mathematical functions describing a theoretical concept of Hydrological cycle. Blackbox - Mathematical functions which is filled to the data without regard to the process it represents. Continuous - Stimulate long periods of time without being RESET, to the observed data, such models require some form of moisture storage accounting. Event - Designed to stimulate a single runoff event given in initial condition. Complete - Includes computing algorithms of the volume of runoff from rainfall and distributing this volume in a form of HYDROGRAPH.



First quantitative experiment in Hydrology

Experimental data confirming Perrault

Demonstrated that evaporation from the oceans was adequate to supply continental precipitation

Measurement of evaporation leading eventually to the development of Dalton‟s law

Preparation of Hydraulic tables

Rational Formula – first known hydrological model

“English rainfall” - publication

Introduced first „telegraphic current meter‟ – making flow measurement in streams easier and reliable

First to introduce concept of frequency into hydrology

Elements in Hydrology

Extensive discussions on interception

Published – „Flood Flows‟ – probabilistic aspects of hydrology

Concept of „Unit Hydrograph‟

Presented theory of infiltration

Derived – Hydrograph of overland flow, catchments of different shapes using velocity of flow as a parameter

First approach to „Kinematic Routing‟ – then known as „Muskingum‟ routing

Described process of interflow Elementary moisture accounting procedure using measured evaporations and simple infiltration process to calculate daily runoff values

Concept of potential evapotranspiration

Used runoff coefficients in drainage design in Ireland

Digital computation to route flows in river basin Using daily rainfall (hourly flow), simple infiltration function, combination of Unit hydrographs and recession function – produce mean daily flow hydrographs

„Tank type model‟

Event model – designed to stimulate individual storm events

Described the model of three dimensional transient saturated/unsaturated groundwater flow

2.3 Chronology



Ahmedabad As viewed by Cartosat 1A and Cartosat 2A merged product. Source : Space Application Center, ISRO, Ahmedabad.

Paldi As viewed by IRS-P6, LISS IV. Source : Space Application Center, ISRO, Ahmedabad

Paldi area of Ahmedabad city was taken as a study for urban storm water and hydrological analysis.



Chapter 3 3.1 Introduction Ahmadabad City lies between 22 55‟ and 23 08‟ North Latitude and 72 30‟ and 72 42‟ East longitude. The City has major physical feature, river Sabarmati which divides the city into two parts : eastern walled city and western Ahmadabad on either side of its banks. 3.2 Location and Climate Ahmedabad has a tropical monsoon climate, which is hot and dry, except in the rainy season. Summer days are very hot with mean maximum temperature of 41.3 C while nights are pleasant with mean minimum temperature of 26.3 C .

The mean maximum and minimum temperatures in winter are 30 C and 15.4 C respectively. The average annual rainfall of the area is 782mm, although there is a considerable variation from year to year. It occurs generally during the months of June to September. The average relative humidity is 60 % with a maximum of 80 % to 90% during the rainy season.

Water logging and flooding problems: Negligence of natural drainage in the growth and development of Ahmedabad city has led to problems of water logging and flooding during the monsoons. The city experienced worst floods in 2000 when large areas of western and eastern Ahmedabad were affected.

3.3 Drainage System Storm water drains in the city covers only 23% of the roads in the city. There are three types of drains laid in the city –RCC pipes. Box type drains and arch drains. The storm water drains discharge storm water into Sabarmati River at 42 locations, of which currently only 27 locations are functional. Storm water drains in the city are poorly developed and many parts of the western and eastern zone experience water logging problems during the rainy season. However, the walled city area does not have any problems of flooding/water logging. In the periphery the system is yet to be developed in most parts.

3.4 Topography Ahmedabad is more or less plain area. The maximum height is 70 meters and the minimum height is 36 meters from the mean sea level. The study area lies in the south west part of Ahmedabad, which is at the downstream part and adjacent to the sabarmati river and is relatively low lying area. During higher rainfall this part of the Ahmedabad experiences problems of water loggin in several areas due to steep slopes, high density of residential area, higher imperviousness and absence of storm water channels.

Topography, Paldi Area



3.5 Rainfall The precipitation which starts from the last week of June extends up to the end of September. The region is a moderate rainfall zone and the normal rainfall in the area is about 25 inches. However, variations are considerable from year to year. Rainfall is both erratic and irregular. The rainfall of year 2009 is considered for the study.

Source: Indian Meteorological Data www.imd.gov.in

Wind Speed South west winds are at an average of 4mph and 5 to 6 knots which generally bring rainfall to the whole of Gujarat.

Density The Land use of the studied area is largely residential areas with commercial on the streets. Due enchroachment and slum inhabitants the imperviousness of the area has drastically reduced the rainwater infiltration and subsequently increased runoff and flooding.



Chapter 4 4.1 Stormwater Management and Modeling Storm water Management Model developed by US environmental Protection Agency, is a package of models linked together and divided into a numberof blocks. It is comprehensive model covering both quantity and quality aspects. For models of the Storm Water Management, average percentage of imperviouness is the most sensitive parameter affecting the estimation of runoff amounts and because of currents indexing of pollutants to street loadings, street gutter density is also an important and sensitive parameter affecting the pollutant loadings.

The EPA Storm Water Management Model (SWMM) is a dynamic rainfall-runoff simulation model used for single event or long-term (continuous) simulation of runoff quantity and quality from primarily urban areas. The runoff component of SWMM operates on a collection of subcatchment areas that receive precipitation and generate runoff and pollutant loads. The routing portion of

SWMM transports this runoff through a system of pipes, channels, storage/treatment devices, pumps, and regulators. SWMM tracks the quantity and quality of runoff generated within each subcatchment, and the flow rate, flow depth, and quality of water in each pipe and channel during a simulation period comprised of multiple time steps. SWMM was first developed in 1971 and has undergone several major upgrades since then, It continues to be widely used throughout the world for planning, analysis and design related to storm water runoff, combined sewers, sanitary sewers, and other drainage systems in urban areas, with many applications in non-urban areas as well. Running under Windows, SWMM 5 provides an integrated environment for editing study area input data, running hydrologic, hydraulic and water quality simulations, and viewing the results in a variety of formats. 4.2 Modeling Capabilities SWMM accounts for various hydrologic processes that produce runoff from urban areas. These include: Time-varying rainfall Evaporation of standing surface water Snow accumulation and melting Rainfall interception from depression storage Infiltration of rainfall into unsaturated soil layers Percolation of infiltrated water into groundwater layers Interflow between groundwater and the drainage system Nonlinear reservoir routing of overland flow

Spatial variability in all of these processes is achieved by dividing a study area into a collection of smaller, homogeneous subcatchment areas, each containing its own fraction of pervious and impervious sub-areas. Overland flow can be routed between sub-areas, between subcatchments, or between entry points of a drainage system.



SWMM also contains a flexible set of hydraulic modeling capabilities used to route runoff and external inflows through the drainage system network of pipes, channels, storage/treatment units and diversion structures. These include the ability to: Handle networks of unlimited size Use a wide variety of standard closed and open conduit shapes as well as natural channels Model special elements such as storage/treatment units, flow dividers, pumps, weirs, and orifices Apply external flows and water quality inputs from surface runoff, groundwater interflow,

rainfall-dependent infiltration/inflow, dry weather sanitary flow, and userdefined inflows Utilize either kinematic wave or full dynamic wave flow routing methods Model various flow regimes, such as backwater, surcharging, reverse flow, and Surface ponding Apply user-defined dynamic control rules to simulate the operation of pumps, orifice

openings, and weir crest levels. In addition to modeling the generation and transport of runoff flows, SWMM can also estimate the production of pollutant loads associated with this runoff. The following processes can be modeled for any number of user-defined water quality constituents: dry-weather pollutant buildup over different land uses pollutant washoff from specific land uses during storm events direct contribution of rainfall deposition reduction in dry-weather buildup due to street cleaning reduction in washoff load due to BMPs entry of dry weather sanitary flows and user-specified external inflows at any point in the

drainage system routing of water quality constituents through the drainage system reduction in constituent concentration through treatment in storage units or by natural

processes in pipes and channels.



Existing Sewerage Line, AMC

Issues controlling storm water



Water Logging and flooding problems: Negligence of natural drainage in the growth and development of Ahmedabad city has led to problems of water logging and flooding during the monsoons. The city experienced worst floods in 2000 when large areas of western and eastern Ahmedabad were affected. Poor Coverage: The storm water drains cover only 23% of the roads. The newly acquired areas of AMC do not have storm water drainage system because of which areas of Odhav, Naroda and Vatwa experience water logging. Infiltration of storm water into the sewerage network: Sewer system unauthorized used fordischarging storm water in absence of adequate storm water facilities in many areas. Blockage of outlets and silting of storm water drains: Of the 36 outlets into the river Sabarmati, 9 outlets are blocked. Similar blockage and silting has also been reported in the storm water drains.

Source : Ahmedabad Urban Development Authority, Ahmedabad Municipal Corp. & Cept University, CDP 2006-2

Generated Storm

Existing Storm Water Drainage Line Proposed Storm Water Drainage Line

Problematic Areas

Storm Water Modeling is an event based analysis method, in which several peak value and storm with respect to local climate and their highest recorded values. Based on that a storm is generated, similarly in this simulation, a storm is considered of 4hr.



4.3 Hydrologic Analysis of the Catchment Area

Main Drainage Pipe Line The Main drainage channel follows the south-west ward slope of the city – a relatively low lying area which experiences frequent water logging in monsoon.

Secondary Drainage Pipe Line The Secondary drainage pipe along the river side have further more downward slope towards the river, so maximum runoff is diverted into the river and runoff into the drainage account very less.

Tertiary Drainage Pipe line The tertiary drainage pipe in this area is further downwards towards the railway line, therefore there exists a drainage pump station which pumps the drainage to the main channel.

Pump Station The pumping station on the downward slope, constantly pumps through the day and makes an average of 60,000 gallons per day to the main channel.

Paldi area is prone to water logging every year and it is a dire need to mitigate flooding junctions and street and to route the storm wate. Moreover storm water – not entering drainage creates of subflow below the surface of the road, pavements and forms instant pits due to sliding of land below the surface.

Drainage hierarchy of Paldi Catchment



1

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4.55

4.56

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4.58

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36

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2.539

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150

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188

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Maximum Depth of Conduits

Pervious and Imperviousness Ratio



Analysis of Simulation Results

Node - 162

Subcatchment - 7

Link - 84



Subcatchment - 89

Link - 84

Node - 174



105

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The comparative analysis of the nodes showing individual flooding level in a simulated storm – states the node -105 is more prone to water logging.



Chapter 5

Low Impact Development Introduction

The low impact development (LID) approach has been recommended as an alternative to traditional stormwater design. In India research on LID practices such as bioretention, pervious pavements, and grassed swales is not much into practice, as looking to the present state of Indian cities it is a grave requirement to put these approaches in practice. The effects of traditional development practices on the hydrologic cycle have been well documented. Increases in the impervious surfaces associated with urbanization have resulted in increased surface runoff, increased runoff velocity, decreased time of concentration, and decreased water quality. The earliest documentation of increased runoff from urban areas was in the late 1800s, and urban runoff continues to be a leading cause of impairments in the present cities. Low Impact Development (LID) was piloted in Maryland ( Prince George’s County 1999) as a way to mitigate the negative effects of increasing urbanization and impervious surfaces. The preservation of the pre-development hydrology of a site is the overall goal of LID. In contrast to typical stormwater design, the LID approach advocates for more careful site design is to preserve as much o the site in an undistributed condition, and where disturbance is necessary, reduce the impact to the soils, vegetation, and aquatic systems on the site. In contrast to traditional stormwater treatment, which typically only mitigates peak flow rates, the use of LID will also help to maintain the predevelopment runoff volume. LID principles are based on controlling stormwater at the source by the use of microscale controls that are disturbed throughout the site. This is unlike conventional approaches that typically convey and manage runoff in large facilities located at the base of drainage areas. These multifunctional site designs incorporate alternative stormwater management practices such as functional landscape that act as stormwater facilities, depression storage and open drainage swales. This system of controls can reduce or eliminate the need for a centralized best management practice (BMP) facility for the control of stormwater runoff. Although traditional stormwater control measures have been documented to effectively remove pollutants, the natural hydrology is still negatively affected (inadequate base flow, thermal fluxes or flashy hydrology), which can have detrimental effects on ecosystems, even when water quality is not compromised. LID practices offer an additional benefit in that they can be integrated into the infrastructure and are more cost effective and aesthetically pleasing than traditional, structural stormwater conveyance systems. Conventional stormwater conveyance systems are designed to collect, convey and discharge runoff as efficiently as possible. The intent is to create a highly efficient drainage system, which will prevent on lot flooding, promote good drainage and quickly convey runoff to a BMP or stream. This runoff control system decreases groundwater recharge, increases runoff volume and changes the timing, frequency and rate of discharge. These changes can cause flooding, water quality degradation, stream erosion and the need to construct end of pipe BMPs. Discharge rates using traditional BMPs may be set only to match the predevelopment peak rate for a specific design year. This approach only controls the rate of runoff allowing significant increases in runoff volume, frequency and duration of runoff from the predevelopment conditions and provides the mechanisms for further degradation of receiving waters.



Cluster layouts, grass swales, rain gardens/bioretention areas, and pervious pavements all reduce the ‘effective impervious area’ of a watershed, or the area that is directly connected to the stormwater system.

1. Bioretention Bioretention areas, or rain gardens, are depressed areas in the landscape that are designed to accept stormwater. They can be used in residential and commercial settings, and are typically planted with shrubs, perennials, or trees, and covered with shredded hardwood bark mulch. The benefits of bioretention areas include decreased surface runoff, increased groundwater recharge, and pollutant treatment through variety of processes. Six typical components found in bioretention cells: Grass buffer strips

reduce runoff velocity and filter particulate matter. Sand bed

provides aeration and drainage of the planting soil and assists in the flushing of pollutants from soil materials. Ponding area

provides storage of excess runoff and facilitates the settling of particulates and evaporation of excess water. Organic layer

performs the function of decomposition of organic material by providing a medium for biological growth (such as microorganisms) to degrade petroleum-based pollutants. It also filters pollutants and prevents soil erosion. Planting soil

provides the area for stormwater storage and nutrient uptake by plants. The planting soils contain some clays which adsorb pollutants such as hydrocarbons, heavy metals and nutrients. Vegetation (plants)

functions in the removal of water through evapotranspiration and pollutant removal through nutrient cycling.

2. Bioswales Bioswales or channels are adaptable to a variety of site conditions, are flexible in design and layout, and are relatively inexpensive. Generally open channel systems are most appropriate for smaller drainage areas with mildly sloping topography. Their application is primarily along residential streets and highways. They function as a mechanism to reduce runoff velocity and as filtration/infiltration devices. Sedimentation is the primary pollutant removal mechanism, with additional secondary mechanisms of infiltration and adsorption. In general grass channels are most effective when the flow depth is minimized and detention time is maximized. The stability of the channel or overland flow is dependent on the erodibility of the soils in which the channel is constructed. Decreasing the slope or providing dense cover will aid in both stability and pollutant removal effectiveness. 3. Tree-Box Filters Tree box filters are in-ground containers typically containing street trees in urban areas. Runoff is directed to the tree box, where it is filtered by vegetation and soil before entering a catch basin. Tree box filters adapt bioretention principles used in rain gardens to enhance pollutant removal, improve reliability, standardize and increase ease of construction, and reduce maintenance costs. Tree box filters decrease peak discharge by detaining stormwater volume and by increasing discharge duration. Use of numerous tree box filters in a stormwater drainage area can have an impact on total discharge energy and flow rates. 4. Permeable Pavements



The use of permeable pavements is an effective means of reducing the percent of imperviousness in a drainage basin. More than thirty different studies have documented that stream, lake and wetland quality is reduced sharply when impervious cover in an upstream watershed is greater than 10%. Porous pavements are best suited for low traffic areas, such as parking lots and sidewalks. The most successful installations of alternative pavements are found in coastal areas with sandy soils and flatter slopes. Permeable pavements allow stormwater to infiltrate into underlying soils promoting pollutant treatment and recharge, as opposed to producing large volumes of rainfall runoff requiring conveyance and treatment.



Project Report - Simulation Results Storm Water Managament Modelling of Paldi Catchment area. **************** Analysis Options **************** Flow Units ............... CFS Infiltration Method ...... HORTON Flow Routing Method ...... KINWAVE Starting Date ............ JUN-01-2009 00:00:00 Ending Date .............. JUN-02-2009 12:00:00 Antecedent Dry Days ...... 5.0 Report Time Step ......... 00:15:00 Wet Time Step ............ 00:15:00 Dry Time Step ............ 01:00:00 Routing Time Step ........ 60.00 sec ************************** Volume Depth Runoff Quantity Continuity acre-feet inches ************************** --------- ------- Total Precipitation ...... 258.493 9.387 Evaporation Loss ......... 1.724 0.063 Infiltration Loss ........ 56.495 2.052 Surface Runoff ........... 201.503 7.318 Final Surface Storage .... 0.000 0.000 Continuity Error (%) ..... -0.476 ************************** Volume Volume Flow Routing Continuity acre-feet Mgallons ************************** --------- --------- Dry Weather Inflow ....... 0.000 0.000 Wet Weather Inflow ....... 201.755 65.745 Groundwater Inflow ....... 0.000 0.000 RDII Inflow .............. 0.000 0.000 External Inflow .......... 0.000 0.000 External Outflow ......... 2.635 0.859 Surface Flooding ......... 198.571 64.707 Evaporation Loss ......... 0.000 0.000 Initial Stored Volume .... 0.000 0.000 Final Stored Volume ...... 4.124 1.344 Continuity Error (%) ..... -1.772

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Storm Water Management & Modelling - a study of Paldi Catchment area


Project Report - Simulation Results

*************************** Subcatchment Runoff Summary *************************** -------------------------------------------------------------------------------------- Total Total Total Total Total Peak Runoff Precip Runon Evap Infil Runoff Runoff Coeff Subcatchment in in in in in CFS -------------------------------------------------------------------------------------- 1 9.388 0.000 0.089 2.255 7.090 13.36 0.755 2 9.388 0.000 0.072 1.561 7.804 5.20 0.831 3 9.388 0.000 0.074 2.463 6.884 10.62 0.733 4 9.388 0.000 0.077 1.711 7.645 5.90 0.814 5 9.388 0.000 0.075 1.849 7.508 3.44 0.800 6 9.388 0.000 0.060 2.613 6.746 3.20 0.719 7 9.388 0.000 0.082 3.311 6.018 40.78 0.641 8 9.388 0.000 0.065 2.799 6.555 3.40 0.698 9 9.388 0.000 0.060 1.464 7.911 3.56 0.843 10 9.388 0.000 0.058 1.681 7.698 5.78 0.820 11 9.388 0.000 0.064 1.798 7.570 24.84 0.806 12 9.388 0.000 0.058 1.895 7.482 10.09 0.797 13 9.388 0.000 0.055 1.812 7.578 1.84 0.807 14 9.388 0.000 0.059 1.498 7.882 2.00 0.840 15 9.388 0.000 0.053 1.987 7.399 3.98 0.788 16 9.388 0.000 0.059 1.522 7.852 3.97 0.836 17 9.388 0.000 0.056 1.829 7.556 6.30 0.805 18 9.388 0.000 0.059 1.578 7.797 4.11 0.831 19 9.388 0.000 0.059 1.874 7.501 13.91 0.799 20 9.388 0.000 0.059 1.855 7.520 11.90 0.801 21 9.388 0.000 0.057 2.234 7.136 19.48 0.760 22 9.388 0.000 0.089 3.052 6.276 21.55 0.669 23 9.388 0.000 0.056 2.051 7.326 10.88 0.780 24 9.388 0.000 0.061 1.780 7.594 17.13 0.809 25 9.388 0.000 0.057 1.927 7.449 10.35 0.794 27 9.388 0.000 0.060 2.043 7.327 19.43 0.781 28 9.388 0.000 0.063 1.565 7.817 11.08 0.833 29 9.388 0.000 0.057 1.977 7.401 9.60 0.788 30 9.388 0.000 0.058 1.652 7.726 5.66 0.823 31 9.388 0.000 0.060 1.805 7.570 16.38 0.806 32 9.388 0.000 0.059 1.616 7.760 5.03 0.827 33 9.388 0.000 0.061 2.014 7.356 23.53 0.784 34 9.388 0.000 0.058 1.903 7.473 10.83 0.796 35 9.388 0.000 0.062 1.570 7.808 8.67 0.832 36 9.388 0.000 0.054 1.927 7.458 3.68 0.794

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Project Report - Simulation Results 37 9.388 0.000 0.063 2.788 6.569 11.88 0.700 38 9.388 0.000 0.056 1.854 7.531 6.10 0.802 39 9.388 0.000 0.061 1.652 7.729 8.22 0.823 40 9.388 0.000 0.060 1.460 7.916 3.24 0.843 41 9.388 0.000 0.053 2.255 7.128 8.47 0.759 42 9.388 0.000 0.052 2.028 7.360 3.25 0.784 43 9.388 0.000 0.056 1.785 7.598 3.33 0.809 44 9.388 0.000 0.055 1.842 7.541 5.31 0.803 45 9.388 0.000 0.053 2.562 6.814 15.02 0.726 46 9.388 0.000 0.058 1.611 7.772 2.47 0.828 47 9.388 0.000 0.057 1.663 7.721 2.40 0.822 48 9.388 0.000 0.054 1.945 7.440 4.78 0.793 49 9.388 0.000 0.054 1.892 7.500 1.86 0.799 50 9.388 0.000 0.055 1.786 7.603 1.87 0.810 51 9.388 0.000 0.058 1.820 7.566 7.81 0.806 52 9.388 0.000 0.057 1.716 7.662 4.24 0.816 53 9.388 0.000 0.054 1.849 7.541 2.34 0.803 54 9.388 0.000 0.056 1.687 7.698 2.26 0.820 55 9.388 0.000 0.058 1.419 7.966 1.46 0.849 56 9.388 0.000 0.050 2.157 7.243 1.83 0.772 57 9.388 0.000 0.056 2.045 7.332 12.94 0.781 58 9.388 0.000 0.062 1.606 7.775 9.33 0.828 59 9.388 0.000 0.059 2.093 7.278 17.99 0.775 60 9.388 0.000 0.058 2.151 7.221 17.55 0.769 61 9.388 0.000 0.058 1.627 7.752 3.62 0.826 62 9.388 0.000 0.058 1.599 7.779 3.56 0.829 63 9.388 0.000 0.055 1.864 7.519 4.93 0.801 64 9.388 0.000 0.059 1.515 7.862 3.32 0.838 65 9.388 0.000 0.057 1.953 7.424 10.05 0.791 66 9.388 0.000 0.061 1.940 7.436 17.83 0.792 67 9.388 0.000 0.061 1.696 7.677 14.14 0.818 68 9.388 0.000 0.063 1.347 8.022 5.60 0.855 69 9.388 0.000 0.058 1.696 7.685 7.02 0.819 70 9.388 0.000 0.051 2.208 7.187 5.25 0.766 71 9.388 0.000 0.060 1.696 7.688 9.53 0.819 72 9.388 0.000 0.061 1.700 7.675 10.98 0.818 73 9.388 0.000 0.058 1.885 7.503 8.32 0.799 74 9.388 0.000 0.060 1.772 7.601 12.59 0.810 75 9.388 0.000 0.055 1.822 7.566 2.37 0.806 76 9.388 0.000 0.054 1.904 7.480 3.97 0.797 77 9.388 0.000 0.055 1.841 7.542 5.25 0.803 78 9.388 0.000 0.063 1.903 7.466 26.03 0.795 79 9.388 0.000 0.063 1.526 7.853 10.08 0.837 80 9.388 0.000 0.062 1.380 7.991 6.24 0.851 81 9.388 0.000 0.060 1.756 7.618 10.81 0.812 82 9.388 0.000 0.062 1.595 7.789 11.09 0.830

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Project Report - Simulation Results 83 9.388 0.000 0.057 1.780 7.604 6.88 0.810 84 9.388 0.000 0.059 2.142 7.228 23.33 0.770 85 9.388 0.000 0.062 1.923 7.446 24.30 0.793 86 9.388 0.000 0.061 1.595 7.783 8.34 0.829 87 9.388 0.000 0.047 2.790 6.626 1.85 0.706 88 9.388 0.000 0.059 1.542 7.835 3.35 0.835 89 9.388 0.000 0.065 1.866 7.502 30.53 0.799 90 9.388 0.000 0.066 1.885 7.484 33.52 0.797 91 9.388 0.000 0.062 1.901 7.468 21.39 0.796 92 9.388 0.000 0.060 2.023 7.346 20.77 0.783 93 9.388 0.000 0.067 3.553 5.789 23.37 0.617 94 9.388 0.000 0.065 1.938 7.431 31.36 0.792 95 9.388 0.000 0.063 1.816 7.554 22.61 0.805 96 9.388 0.000 0.059 2.068 7.308 15.13 0.779 97 9.388 0.000 0.065 1.150 8.217 4.61 0.875 98 9.388 0.000 0.057 1.692 7.686 4.47 0.819 99 9.388 0.000 0.054 1.910 7.479 2.74 0.797 100 9.388 0.000 0.055 1.868 7.516 5.15 0.801 101 9.388 0.000 0.050 2.012 7.392 1.13 0.787 102 9.388 0.000 0.056 1.803 7.581 6.53 0.808 103 9.388 0.000 0.049 2.280 7.177 0.74 0.765 -------------------------------------------------------------------------------------- System 9.388 0.000 0.063 2.052 7.318 1012.01 0.780

****************** Node Depth Summary ****************** ---------------------------------------------------------------------------------------- Average Maximum Maximum Time of Max Total Total Depth Depth HGL Occurrence Flooding Minutes Node Type Feet Feet Feet days hr:min acre-in Flooded ---------------------------------------------------------------------------------------- 104 JUNCTION 0.34 4.50 4.50 0 03:52 0.08 59 105 JUNCTION 1.68 4.50 4.50 0 01:19 86.25 383 106 JUNCTION 2.83 4.50 4.50 0 01:17 142.70 718 107 JUNCTION 3.10 4.50 4.50 0 03:47 0.15 410 108 JUNCTION 2.68 4.50 4.50 0 01:43 9.04 248 109 JUNCTION 3.66 4.50 4.50 0 01:28 47.60 1032

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Project Report - Simulation Results 110 JUNCTION 2.70 4.50 4.50 0 07:25 0 93 111 JUNCTION 4.02 4.50 4.50 0 03:51 0 1930 115 JUNCTION 0.18 1.50 1.50 0 01:16 107.02 255 116 JUNCTION 1.44 2.50 2.50 0 01:17 73.19 265 118 JUNCTION 0.12 1.00 1.00 0 01:16 75.89 254 119 JUNCTION 1.10 4.50 4.50 0 04:55 0.02 21 120 JUNCTION 0.73 1.50 1.50 0 01:17 49.50 540 121 JUNCTION 0.89 1.50 1.50 0 01:17 25.33 403 122 JUNCTION 1.05 2.50 2.50 0 01:18 39.39 252 123 JUNCTION 2.13 2.50 2.50 0 01:17 32.63 1306 124 JUNCTION 1.49 2.50 2.50 0 02:59 0.43 395 125 JUNCTION 1.36 2.50 2.50 0 01:23 10.79 240 126 JUNCTION 0.18 1.50 1.50 0 01:16 60.98 258 127 JUNCTION 0.12 1.00 1.00 0 01:16 60.12 264 128 JUNCTION 0.37 0.66 0.66 0 05:45 0 0 129 JUNCTION 0.65 3.00 3.00 0 01:18 52.84 263 130 JUNCTION 0.71 2.00 2.00 0 01:41 5.12 415 131 JUNCTION 1.30 1.50 1.50 0 01:16 9.19 1530 132 JUNCTION 0.45 1.00 1.00 0 01:16 65.93 270 133 JUNCTION 0.72 1.25 1.25 0 01:16 110.99 284 134 JUNCTION 0.63 1.25 1.25 0 01:16 50.86 268 135 JUNCTION 0.24 1.00 1.00 0 05:45 0 1 136 JUNCTION 0.45 1.00 1.00 0 04:52 0.10 433 137 JUNCTION 0.11 1.00 1.00 0 01:16 10.68 240 138 JUNCTION 0.12 1.00 1.00 0 01:16 54.95 269 139 JUNCTION 0.12 1.00 1.00 0 01:16 18.64 248 140 JUNCTION 1.34 2.00 2.00 0 01:17 34.76 323 141 JUNCTION 1.42 2.00 2.00 0 01:16 66.57 295 142 JUNCTION 0.45 1.00 1.00 0 01:16 27.59 255 143 JUNCTION 0.47 1.50 1.50 0 01:16 39.05 277 144 JUNCTION 0.80 1.50 1.50 0 01:17 14.13 392 145 JUNCTION 0.22 1.00 1.00 0 01:17 7.72 303 146 JUNCTION 0.11 1.00 1.00 0 01:17 8.51 239 147 JUNCTION 0.24 1.50 1.50 0 01:16 31.93 316 148 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 149 JUNCTION 1.06 1.50 1.50 0 01:16 21.24 901 156 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 157 JUNCTION 0.13 1.00 1.00 0 01:16 45.56 271 158 JUNCTION 0.44 1.50 1.50 0 01:21 4.34 234 159 JUNCTION 0.13 1.00 1.00 0 01:16 59.88 274 161 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 162 JUNCTION 0.29 1.50 1.50 0 01:16 99.75 417 163 JUNCTION 0.85 1.50 1.50 0 01:20 7.56 511 164 JUNCTION 0.49 1.00 1.00 0 01:16 12.63 280 165 JUNCTION 0.16 1.00 1.00 0 01:16 25.41 345 166 JUNCTION 0.00 0.00 0.00 0 00:00 0 0

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Project Report - Simulation Results 167 JUNCTION 0.48 1.00 1.00 0 01:18 7.31 334 168 JUNCTION 0.00 0.00 0.00 0 00:00 0 0 169 JUNCTION 2.89 3.00 3.00 0 01:20 0 2081 172 JUNCTION 0.82 1.25 1.25 0 01:16 114.90 359 173 JUNCTION 0.96 1.25 1.25 0 01:16 49.28 745 174 JUNCTION 1.10 1.25 1.25 0 01:16 154.56 1667 175 JUNCTION 0.12 1.00 1.00 0 01:16 31.69 253 176 JUNCTION 0.27 1.00 1.00 0 01:16 27.00 338 177 JUNCTION 0.65 2.00 2.00 0 01:18 20.70 286 178 JUNCTION 0.60 1.50 1.50 0 01:16 61.50 351 179 JUNCTION 0.11 1.00 1.00 0 01:16 19.00 240 180 JUNCTION 0.14 1.00 1.00 0 01:17 26.80 296 181 JUNCTION 0.12 1.00 1.00 0 01:16 49.46 255 182 JUNCTION 0.12 1.00 1.00 0 01:16 39.10 265 184 JUNCTION 0.25 2.00 2.00 0 01:17 56.27 263 185 JUNCTION 0.22 2.00 2.00 0 01:21 18.23 235 OUT3 OUTFALL 0.96 1.00 1.00 0 01:23 0 0

***************** Node Flow Summary ***************** ------------------------------------------------------------------------------------ Maximum Maximum Maximum Lateral Total Time of Max Flooding Time of Max Inflow Inflow Occurrence Overflow Occurrence Node Type CFS CFS days hr:min CFS days hr:min ------------------------------------------------------------------------------------ 104 JUNCTION 1.83 1.83 0 04:45 0.27 0 04:45 105 JUNCTION 35.84 37.83 0 04:45 36.50 0 04:45 106 JUNCTION 61.67 62.02 0 04:45 60.61 0 04:45 107 JUNCTION 1.87 2.29 0 04:45 0.40 0 04:45 108 JUNCTION 5.66 6.49 0 04:03 4.79 0 04:04 109 JUNCTION 21.65 22.74 0 04:45 21.14 0 04:45 110 JUNCTION 0.00 1.53 0 16:31 0.00 111 JUNCTION 0.00 1.41 0 12:12 0.00 115 JUNCTION 44.51 44.51 0 04:45 44.32 0 04:45 116 JUNCTION 31.33 31.44 0 04:45 30.96 0 04:45 118 JUNCTION 31.53 31.53 0 04:45 31.37 0 04:45 119 JUNCTION 2.34 3.48 0 04:55 0.27 0 04:56

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Project Report - Simulation Results 120 JUNCTION 21.55 21.70 0 04:45 21.54 0 04:46 121 JUNCTION 10.88 10.93 0 04:45 10.79 0 04:45 122 JUNCTION 17.13 17.27 0 04:45 16.67 0 04:45 123 JUNCTION 12.68 13.26 0 04:45 12.93 0 04:45 124 JUNCTION 0.00 0.51 0 05:31 0.17 0 05:31 125 JUNCTION 5.03 5.28 0 04:45 4.76 0 04:45 126 JUNCTION 25.56 25.56 0 04:45 25.40 0 04:45 127 JUNCTION 24.95 24.95 0 04:45 24.86 0 04:45 128 JUNCTION 0.00 0.02 0 05:45 0.00 129 JUNCTION 23.33 23.33 0 04:45 22.73 0 04:45 130 JUNCTION 1.85 2.15 0 04:45 2.05 0 04:45 131 JUNCTION 3.35 3.47 0 04:45 3.43 0 04:45 132 JUNCTION 27.22 27.23 0 04:45 27.12 0 04:45 133 JUNCTION 46.49 46.50 0 04:45 46.31 0 04:45 134 JUNCTION 21.39 21.39 0 04:45 21.23 0 04:45 135 JUNCTION 0.00 0.04 0 05:57 0.00 136 JUNCTION 0.00 0.05 0 07:15 0.03 0 07:16 137 JUNCTION 4.47 4.47 0 04:45 4.43 0 04:45 138 JUNCTION 23.08 23.08 0 04:45 22.97 0 04:45 139 JUNCTION 7.88 7.88 0 04:45 7.83 0 04:45 140 JUNCTION 13.86 14.38 0 04:45 14.16 0 04:45 141 JUNCTION 28.23 28.30 0 04:45 28.01 0 04:45 142 JUNCTION 11.81 11.82 0 04:45 11.75 0 04:45 143 JUNCTION 16.38 16.52 0 04:45 16.36 0 04:45 144 JUNCTION 5.90 5.91 0 04:45 5.80 0 04:45 145 JUNCTION 3.25 3.31 0 04:45 3.27 0 04:45 146 JUNCTION 3.68 3.68 0 04:45 3.61 0 04:45 147 JUNCTION 13.36 13.36 0 04:45 13.25 0 04:45 148 JUNCTION 0.00 0.00 0 00:00 0.00 149 JUNCTION 8.83 8.87 0 04:45 8.76 0 04:45 156 JUNCTION 0.00 0.00 0 00:00 0.00 157 JUNCTION 19.48 19.48 0 04:45 19.39 0 04:45 158 JUNCTION 2.00 2.01 0 04:45 1.86 0 04:45 159 JUNCTION 24.84 24.84 0 04:45 24.74 0 04:45 161 JUNCTION 0.00 0.00 0 00:00 0.00 162 JUNCTION 40.78 40.78 0 04:45 40.63 0 04:46 163 JUNCTION 3.40 3.44 0 04:45 3.33 0 04:45 164 JUNCTION 5.20 5.20 0 04:45 5.15 0 04:45 165 JUNCTION 10.62 10.62 0 04:45 10.56 0 04:45 166 JUNCTION 0.00 0.00 0 00:00 0.00 167 JUNCTION 3.20 3.22 0 04:45 3.17 0 04:45 168 JUNCTION 0.00 0.00 0 00:00 0.00 169 JUNCTION 0.00 0.53 0 06:13 0.00 172 JUNCTION 49.40 49.41 0 04:45 49.20 0 04:45 173 JUNCTION 20.77 20.79 0 04:45 20.68 0 04:45 174 JUNCTION 64.04 64.05 0 04:45 63.83 0 04:45

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Project Report - Simulation Results 175 JUNCTION 13.13 13.13 0 04:45 13.04 0 04:45 176 JUNCTION 11.09 11.13 0 04:45 11.08 0 04:45 177 JUNCTION 8.34 8.80 0 04:45 8.46 0 04:45 178 JUNCTION 25.76 25.79 0 04:45 25.63 0 04:45 179 JUNCTION 7.96 7.96 0 04:45 7.87 0 04:45 180 JUNCTION 11.88 11.88 0 04:45 11.77 0 04:45 181 JUNCTION 20.68 20.68 0 04:45 20.55 0 04:45 182 JUNCTION 16.38 16.38 0 04:45 16.26 0 04:45 184 JUNCTION 24.30 24.30 0 04:45 23.78 0 04:45 185 JUNCTION 8.39 8.39 0 04:45 7.91 0 04:45 OUT3 OUTFALL 0.00 0.03 1 02:51 0.00 *********************** Outfall Loading Summary *********************** ----------------------------------------------- Flow Avg. Max. Freq. Flow Flow Outfall Node Pcnt. CFS CFS ----------------------------------------------- OUT3 95.09 0.03 0.03 ----------------------------------------------- System 95.09 0.03 0.03 ******************** Link Flow Summary ******************** ----------------------------------------------------------------------------------------- Maximum Time of Max Maximum Max/ Max/ Total Flow Occurrence Velocity Full Full Minutes Link Type CFS days hr:min ft/sec Flow Depth Surcharged ------------------------------------------------------------------------------------------ 1 CONDUIT 1.56 0 05:26 0.24 1.08 1.00 54 4 CONDUIT 1.23 0 12:29 0.12 1.08 1.00 406 5 CONDUIT 1.24 0 21:48 0.11 1.08 1.00 701 6 CONDUIT 1.88 0 05:22 0.28 1.08 1.00 55 7 CONDUIT 1.70 0 06:38 0.23 1.08 0.86 218 8 CONDUIT 1.53 0 16:31 0.12 1.08 1.00 497 9 CONDUIT 1.41 0 12:12 0.26 0.91 0.74 0 3 CONDUIT 0.07 0 06:27 0.09 1.08 0.72 146 2 CONDUIT 3.20 0 05:17 0.26 1.08 1.00 21 33 CONDUIT 0.10 0 13:40 0.08 1.08 1.00 310

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Project Report - Simulation Results 34 CONDUIT 0.11 0 06:01 0.08 1.08 0.85 69 35 CONDUIT 0.55 0 05:49 0.17 1.08 0.93 98 36 CONDUIT 0.30 1 07:07 0.07 1.08 1.00 822 37 CONDUIT 0.34 0 12:47 0.09 1.08 1.00 309 38 CONDUIT 0.39 0 05:54 0.12 1.08 1.00 78 39 CONDUIT 0.51 0 05:31 0.13 1.08 0.91 26 44 CONDUIT 0.02 0 05:45 0.07 0.76 0.49 0 45 CONDUIT 0.01 0 16:46 0.04 0.33 0.39 0 47 CONDUIT 0.09 0 11:26 0.08 1.08 1.00 237 48 CONDUIT 0.02 0 05:30 0.08 0.80 0.49 0 49 CONDUIT 0.02 0 10:10 0.05 0.62 0.58 0 50 CONDUIT 0.02 0 18:06 0.05 0.81 0.69 0 51 CONDUIT 0.04 0 05:57 0.12 1.08 0.66 38 53 CONDUIT 0.04 0 05:42 0.12 1.08 0.72 40 54 CONDUIT 0.03 0 08:03 0.08 0.56 0.52 0 56 CONDUIT 0.10 0 05:50 0.16 1.08 1.00 77 57 CONDUIT 0.21 0 06:18 0.12 1.08 0.89 50 58 CONDUIT 0.18 0 11:10 0.08 1.08 1.00 212 59 CONDUIT 0.06 0 05:33 0.19 1.08 0.79 79 60 CONDUIT 0.03 0 08:28 0.08 0.86 0.68 0 61 CONDUIT 0.02 0 16:30 0.05 0.75 0.60 0 62 CONDUIT 0.07 0 08:47 0.10 1.08 0.89 202 63 CONDUIT 0.08 0 06:11 0.06 1.02 0.99 18 65 CONDUIT 0.11 0 07:36 0.09 1.08 1.00 159 72 CONDUIT 0.03 1 02:51 0.05 1.05 0.89 778 75 CONDUIT 0.00 0 00:00 0.00 0.00 0.00 0 76 CONDUIT 0.00 0 00:00 0.00 0.00 0.00 0 77 CONDUIT 0.03 0 06:17 0.11 1.08 0.69 53 79 CONDUIT 0.15 0 05:19 0.16 1.08 0.91 21 80 CONDUIT 0.03 0 06:00 0.10 1.08 0.67 41 81 CONDUIT 0.00 0 00:00 0.00 0.00 0.00 0 83 CONDUIT 0.00 0 00:00 0.00 0.00 0.00 0 84 CONDUIT 0.08 0 08:56 0.11 1.08 0.97 101 85 CONDUIT 0.10 0 16:11 0.07 1.08 1.00 504 86 CONDUIT 0.09 1 00:54 0.08 1.08 1.00 637 87 CONDUIT 0.02 0 07:15 0.08 0.92 0.53 0 88 CONDUIT 0.04 0 06:35 0.09 1.08 0.71 58 89 CONDUIT 0.04 0 07:15 0.07 1.04 0.81 30 90 CONDUIT 0.00 0 00:00 0.00 0.00 0.00 0 91 CONDUIT 0.53 0 06:13 0.17 1.08 0.90 62 94 CONDUIT 0.05 0 06:00 0.06 1.02 0.71 13 95 CONDUIT 0.05 0 08:13 0.06 1.00 0.83 0 96 CONDUIT 0.04 0 19:30 0.04 1.00 0.84 0 97 CONDUIT 0.03 0 07:15 0.04 0.81 0.79 0 99 CONDUIT 0.05 0 05:35 0.16 1.08 0.75 20 100 CONDUIT 0.02 0 10:57 0.06 0.74 0.63 0

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Project Report - Simulation Results 101 CONDUIT 0.32 0 06:40 0.17 1.08 1.00 151 102 CONDUIT 0.09 0 06:03 0.13 1.08 0.95 68 103 CONDUIT 0.08 0 08:47 0.07 1.08 0.86 406 105 CONDUIT 0.07 0 05:18 0.23 1.08 0.81 150 106 CONDUIT 0.07 0 05:31 0.23 1.08 0.82 159 107 CONDUIT 0.07 0 06:18 0.23 1.08 0.81 209 108 CONDUIT 0.07 0 05:32 0.23 1.08 0.81 161 109 CONDUIT 0.07 0 05:39 0.23 1.08 0.82 174 110 CONDUIT 0.46 0 05:38 0.36 1.08 1.00 210 111 CONDUIT 0.46 0 05:19 0.36 1.08 0.96 182 ************************* Routing Time Step Summary ************************* Minimum Time Step : 60.00 sec Average Time Step : 60.00 sec Maximum Time Step : 60.00 sec Percent in Steady State : 0.00 Average Iterations per Step : 1.17

Analysis begun on: Wed Jul 28 01:35:33 2010 Total elapsed time: 00:00:01

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Date Rainfall_IMD Temp_IMD Relative Humidity (%)Wind (Kts) Wind_Value(Kts) Wind mph6/1/2009 NIL * * * 0 06/2/2009 NIL * * * 0 06/3/2009 NIL * * * 0 06/4/2009 NIL * * * 0 06/5/2009 NIL * * SSW 3 3 3.452338356/6/2009 NIL * * WNW 6 6 6.90467676/7/2009 NIL * * SW 3 3 3.452338356/8/2009 NIL 41.7 64 W 5 5 5.753897256/9/2009 NIL 41.6 64 SSW 5 5 5.75389725

6/10/2009 NIL 40.2 65 SW 4 4 4.60311786/11/2009 NIL 41.3 62 SW 5 5 5.753897256/12/2009 NIL 41.2 65 SW 5 5 5.753897256/13/2009 NIL 41.5 66 SSW 5 5 5.753897256/14/2009 NIL 41 66 SW 5 5 5.753897256/15/2009 0.5 40.5 69 SW 10 10 11.50779456/16/2009 NIL 41 62 SSW 5 5 5.753897256/17/2009 NIL 40.5 * * 0 06/18/2009 NIL 39.8 * * 0 06/19/2009 2 40.7 66 W 5 5 5.753897256/20/2009 NIL * 63 W 4 4 4.60311786/21/2009 * 41.9 63 W 3 3 3.452338356/22/2009 NIL * 64 SSW 3 3 3.452338356/23/2009 NIL 38.3 71 CALM 0 06/24/2009 NIL 39.2 * * 0 06/25/2009 NIL 37.3 66 SE 8 8 9.20623566/26/2009 NIL 38.4 70 S 5 5 5.753897256/27/2009 NIL 39 * * 0 06/28/2009 NIL * 73 SSW 5 5 5.753897256/29/2009 NIL 39 71 SSW 3 3 3.452338356/30/2009 NIL 37.9 75 SW 3 3 3.45233835 3.8359315

7/1/2009 NIL 39.7 74 SW 5 5 5.753897257/2/2009 NIL * * * 0 07/3/2009 NIL 37 72 SSW 3 3 3.452338357/4/2009 NIL * * * 0 07/5/2009 NIL * * * 0 07/6/2009 NIL 41.8 60 VRB 2 2 2.30155897/7/2009 NIL 40.8 63 VRB 2 2 2.30155897/8/2009 NIL 41.2 72 SW 6 6 6.90467677/9/2009 2 40.3 81 CALM 0 0

7/10/2009 68 35.8 * * 0 07/11/2009 0.7 29.1 90 SSE 3 3 3.452338357/12/2009 NIL 34.4 82 S 5 5 5.753897257/13/2009 NIL 35.3 83 S 3 3 3.452338357/14/2009 3 34.4 79 CALM 0 07/15/2009 86 36.1 94 CALM 0 07/16/2009 * * 94 CALM 0 07/17/2009 0.5 32.8 95 VRB 2 2 2.30155897/18/2009 7 29.4 95 SSW 5 5 5.753897257/19/2009 1 31.9 87 SSW 4 4 4.60311787/20/2009 0.5 33.4 89 CALM 0 07/21/2009 57 33.3 89 VRB 2 2 2.30155897/22/2009 2 31.4 92 WNW 3 3 3.452338357/23/2009 33 31.4 96 CALM 0 07/24/2009 3 29.4 92 SW 5 5 5.75389725

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7/25/2009 7 29.4 94 SW 5 5 5.753897257/26/2009 9 28.6 92 SW 5 5 5.753897257/27/2009 * * 84 SW 6 6 6.90467677/28/2009 0.2 32.6 86 S 4 4 4.60311787/29/2009 NIL 32.5 87 S 5 5 5.753897257/30/2009 NIL 32.5 83 SW 6 6 6.90467677/31/2009 NIL 33.7 79 SW 4 4 4.6031178 3.155363

8/1/2009 NIL * 86 VRB 2 2 2.30155898/2/2009 NIL 33.6 84 SSW 4 4 4.60311788/3/2009 NIL 33.2 81 SSW 4 4 4.60311788/4/2009 NIL 35 81 S 6 6 6.90467678/5/2009 NIL 32.6 78 SW 5 5 5.753897258/6/2009 0.4 33.2 82 S 6 6 6.90467678/7/2009 NIL 34 76 SSW 6 6 6.90467678/8/2009 NIL 34.4 82 SSW 4 4 4.60311788/9/2009 NIL 35 79 S 5 5 5.75389725

8/10/2009 NIL 34.7 80 S 6 6 6.90467678/11/2009 NIL 34.2 79 VRB 2 2 2.30155898/12/2009 NIL 35.5 75 SSW 4 4 4.60311788/13/2009 NIL 35.5 75 VRB 2 2 2.30155898/14/2009 NIL 35.5 75 SW 4 4 4.60311788/15/2009 NIL 35.1 80 SSE 4 4 4.60311788/16/2009 2 33.5 80 CALM 0 08/17/2009 2 35 83 VRB 2 2 2.30155898/18/2009 0.7 35 80 SW 3 3 3.452338358/19/2009 NIL 35.6 76 W 3 3 3.452338358/20/2009 NIL 35.5 79 WNW 3 3 3.452338358/21/2009 NIL 35.5 78 VRB 2 2 2.30155898/22/2009 NIL 35.9 76 WSW 3 3 3.452338358/23/2009 NIL 34.9 75 WNW 4 4 4.60311788/24/2009 NIL 36 82 VRB 2 2 2.30155898/25/2009 NIL 36 77 VRB 2 2 2.30155898/26/2009 0.4 36.4 80 WSW 8 8 9.20623568/27/2009 0.1 34.4 80 WSW 6 6 6.90467678/28/2009 20 32 90 W 6 6 6.90467678/29/2009 37 30.6 95 CALM 0 08/30/2009 85 28 94 SW 6 6 6.90467678/31/2009 * * 92 S 4 4 4.6031178 4.3803863

9/1/2009 0.4 33.2 85 CALM 0 09/2/2009 2 32.8 89 CALM 0 09/3/2009 NIL 32.2 82 SE 4 4 4.60311789/4/2009 NIL 33.6 87 W 4 4 4.60311789/5/2009 NIL 34.4 90 VRB 2 2 2.30155899/6/2009 NIL 34.6 85 CALM 0 09/7/2009 NIL 34 80 NW 4 4 4.60311789/8/2009 NIL 34.4 82 W 4 4 4.60311789/9/2009 NIL 34.7 85 W 5 5 5.75389725

9/10/2009 NIL 34.8 80 VRB 2 2 2.30155899/11/2009 NIL 34.3 80 SW 5 5 5.753897259/12/2009 NIL 34.2 74 NW 3 3 3.452338359/13/2009 NIL 35 73 VRB 2 2 2.30155899/14/2009 NIL 35.8 77 VRB 2 2 2.30155899/15/2009 20 35.1 78 W 4 4 4.60311789/16/2009 NIL 34.3 77 W 3 3 3.452338359/17/2009 NIL 34.3 73 VRB 2 2 2.30155899/18/2009 NIL 35 70 VRB 2 2 2.3015589

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9/19/2009 NIL 35.8 73 WNW 6 6 6.90467679/20/2009 NIL * 81 WNW 4 4 4.60311789/21/2009 NIL 35.9 84 NNW 5 5 5.753897259/22/2009 NIL 34.8 86 VRB 2 2 2.30155899/23/2009 NIL 36.4 80 W 3 3 3.452338359/24/2009 NIL 38.2 80 CALM 0 09/25/2009 NIL 37 79 W 5 5 5.753897259/26/2009 NIL 35.9 80 CALM 0 09/27/2009 NIL 35.9 74 WNW 3 3 3.452338359/28/2009 NIL * 70 W 6 6 6.90467679/29/2009 NIL * * * 0 0 3.25392819/30/2009 NIL * * * 0 0

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Catch_ID AREA BUILT_UP % PERV. % IMPERV. N-Imper N-Perv D-Imper D-Perv1 18483 11644 37 63 0.012 0.13 0.05 0.052 6668.44 3196.73 52 48 0.012 0.13 0.05 0.053 15023.98 4618.74 69 31 0.012 0.13 0.05 0.054 7712.45 3629.14 53 47 0.012 0.13 0.05 0.055 4558.59 1939.29 57 43 0.012 0.13 0.05 0.056 4481.81 747.71 83 17 0.012 0.13 0.05 0.057 67440.35 14177.13 79 21 0.012 0.13 0.05 0.058 4880.47 873.59 82 18 0.012 0.13 0.05 0.059 4487.03 1995.85 56 44 0.012 0.13 0.05 0.05

10 7339.23 2699.4 63 37 0.012 0.13 0.05 0.0511 32079.87 12216.09 62 38 0.012 0.13 0.05 0.0512 13019.1 4004.34 69 31 0.012 0.13 0.05 0.0513 2370.09 708.78 70 30 0.012 0.13 0.05 0.0514 2512.6 1044.87 58 42 0.012 0.13 0.05 0.0515 5167.05 1316.32 75 25 0.012 0.13 0.05 0.0516 5004.83 2089.75 58 42 0.012 0.13 0.05 0.0517 8083.81 2603.77 68 32 0.012 0.13 0.05 0.0518 5194.19 2064.24 60 40 0.012 0.13 0.05 0.0519 17961.27 5877.55 67 33 0.012 0.13 0.05 0.0520 15313.97 5054.84 67 33 0.012 0.13 0.05 0.0521 25915.72 6075.45 77 23 0.012 0.13 0.05 0.0522 31797.83 4019.13 87 13 0.012 0.4 0.05 0.0523 14190.12 3739.53 74 26 0.012 0.13 0.05 0.0524 22000.12 8123.61 63 37 0.012 0.13 0.05 0.0525 13381.8 3998.18 70 30 0.012 0.13 0.05 0.0526 0.012 0.13 0.05 0.0527 25494.95 7373.51 71 29 0.012 0.13 0.05 0.0528 13978.34 6005.42 57 43 0.012 0.13 0.05 0.0529 12425.4 3500.3 72 28 0.012 0.13 0.05 0.0530 7191.24 2747.51 62 38 0.012 0.13 0.05 0.0531 21060.07 7617.51 64 36 0.012 0.13 0.05 0.0532 6388.03 2467.52 61 39 0.012 0.13 0.05 0.0533 30871.91 9486.77 69 31 0.012 0.13 0.05 0.0534 13968.52 4356.84 69 31 0.012 0.13 0.05 0.0535 10959.43 4593.69 58 42 0.012 0.13 0.05 0.0536 4739.88 1292.16 73 27 0.012 0.13 0.05 0.0537 16730.14 2239 87 13 0.012 0.4 0.05 0.0538 7837.32 2458.48 69 31 0.012 0.13 0.05 0.0539 10435.04 4032.27 61 39 0.012 0.13 0.05 0.0540 4052.81 1789.56 56 44 0.012 0.13 0.05 0.0541 11207.21 2039.45 82 18 0.012 0.13 0.05 0.0542 4224.61 965.27 77 23 0.012 0.13 0.05 0.0543 4268.66 1363.59 68 32 0.012 0.13 0.05 0.0544 6808.83 2108 69 31 0.012 0.13 0.05 0.0545 20429.62 2247.07 89 11 0.012 0.13 0.05 0.0546 3136.47 1182.45 62 38 0.012 0.13 0.05 0.0547 3070.32 1118.64 64 36 0.012 0.13 0.05 0.0548 6155.03 1663.23 73 27 0.012 0.13 0.05 0.0549 2401.92 645.54 73 27 0.012 0.13 0.05 0.0550 2410.6 748.3 69 31 0.012 0.13 0.05 0.0551 10000.81 3307.58 67 33 0.012 0.13 0.05 0.0552 5413.98 1910.76 65 35 0.012 0.13 0.05 0.0553 3018.4 862.14 71 29 0.012 0.13 0.05 0.0554 2896.69 1017.86 65 35 0.012 0.13 0.05 0.0555 1836.27 835.04 55 45 0.012 0.13 0.05 0.0556 2415.33 400 83 17 0.012 0.13 0.05 0.0557 16897.67 4500.82 73 27 0.012 0.13 0.05 0.05

Catchment Properties

ANNEXURE - II



58 11790.68 4826.49 59 41 0.012 0.13 0.05 0.0559 23672.41 6396.45 73 27 0.012 0.13 0.05 0.0560 23151.8 5730.74 75 25 0.012 0.13 0.05 0.0561 4589.78 1745.94 62 38 0.012 0.13 0.05 0.0562 4503.58 1733.89 61 39 0.012 0.13 0.05 0.0563 6339.35 1905.05 70 30 0.012 0.13 0.05 0.0564 4169.12 1769.52 58 42 0.012 0.13 0.05 0.0565 13006.95 3818.54 71 29 0.012 0.13 0.05 0.0566 23167 7416.33 68 32 0.012 0.13 0.05 0.0567 18031.32 6966.85 61 39 0.012 0.13 0.05 0.0568 6970.52 3439.76 51 49 0.012 0.13 0.05 0.0569 8915.03 3321.31 63 37 0.012 0.13 0.05 0.0570 6899.83 1228.2 82 18 0.012 0.13 0.05 0.0571 12124.67 4621.32 62 38 0.012 0.13 0.05 0.0572 13987.21 5381.41 62 38 0.012 0.13 0.05 0.0573 10692.1 3322.14 69 31 0.012 0.13 0.05 0.0574 16122.5 5799.47 64 36 0.012 0.13 0.05 0.0575 3049.5 923.74 70 30 0.012 0.13 0.05 0.0576 5131.48 1421.52 72 28 0.012 0.13 0.05 0.0577 6726.77 2086.26 69 31 0.012 0.13 0.05 0.0578 33907.17 11728.42 65 35 0.012 0.13 0.05 0.0579 12704.33 5550.28 56 44 0.012 0.13 0.05 0.0580 7781.61 3746.6 52 48 0.012 0.13 0.05 0.0581 13834.07 4979.96 64 36 0.012 0.13 0.05 0.0582 14004.36 5925.88 58 42 0.012 0.13 0.05 0.0583 8817.39 3039.73 66 34 0.012 0.13 0.05 0.0584 30889.65 8349.78 73 27 0.012 0.13 0.05 0.0585 31660.44 10841.12 66 34 0.012 0.13 0.05 0.0586 10540.77 4359.21 59 41 0.012 0.13 0.05 0.0587 2530.49 0 100 0 0.15 0.4 0.05 0.0588 4216.25 1738.58 59 41 0.012 0.13 0.05 0.0589 39706.53 14816.86 63 37 0.012 0.13 0.05 0.0590 43722.14 16024.11 63 37 0.012 0.13 0.05 0.0591 27793.74 9446.78 66 34 0.012 0.13 0.05 0.0592 27227.06 8280.47 70 30 0.012 0.13 0.05 0.0593 36761.04 1233.76 97 3 0.012 0.4 0.05 0.0594 41070.08 14412.36 65 35 0.012 0.13 0.05 0.0595 29201.45 10940.88 63 37 0.012 0.13 0.05 0.0596 19808.05 5434.53 73 27 0.012 0.13 0.05 0.0597 5671 3154.28 44 56 0.012 0.13 0.05 0.0598 5675.28 2047.77 64 36 0.012 0.13 0.05 0.0599 3522.55 960.66 73 27 0.012 0.13 0.05 0.05

100 6608.04 1993.77 70 30 0.012 0.13 0.05 0.05101 1482.84 329.57 78 22 0.012 0.13 0.05 0.05102 8373.51 2771.75 67 33 0.012 0.13 0.05 0.05103 992.02 126.21 87 13 0.012 0.13 0.05 0.05

1339336.7 421422.56 69 31



Glossary Algae Simple aquatic plants that may be attached or free floating (planktonic) and occur as single cells, colonies, branched or unbranched filaments. Algal bloom Dense growth of planktonic algae or most commonly cyanobacteria (blue-green bacteria formerly classified as algae) in nutrient enriched surface water bodies causing discolouration of water. Amenity A (SUDS) feature that increases aesthetic attractiveness or provides social or environmental value, of a geographic location Antecedent conditions The condition of a catchment before a rainfall event. Antecedent precipitation The relevant rainfall that takes place prior to the point in time of interest. Aquatic bench A shallow horizontal strip just beneath the water surface around the perimeter of a pond on which aquatic planting is established Aquifer A sub-surface zone or formation of rock or soil containing groundwater. Attenuation (of flow) Reduction of peak flow and increased duration of flow. Attenuation storage A storage unit designed to attenuate flows by limiting flow rates out of it and storing the difference between the in-flow and out-flow temporarily, and releasing it as in-flows reduce/ cease. Baffle A device designed to encourage mixing of flows to prevent short-circuiting through a pond. Also, a device designed to prevent floating solids or liquids from passing forwards from their current location. Base flow Dry-weather flows not directly generated by rainfall. It commonly constitutes flows generated by domestic and industrial discharges but can also be associated with long term infiltration or groundwater discharge. Basin A depression acting as a storage unit to control stormwater flow during rainfall, but is dry at other times. Biochemical oxygen demand (BOD) The measure of the concentration of biodegradable organic carbon compounds in solution. Used as a water quality indicator. Biodegradation Decomposition of organic matter by micro-organisms and other living things. Biodiversity A measure of the diversity of plant and animal life in a particular habitat Bioretention A drainage practice that utilizes landscaping and soils to treat urban stormwater runoff, filtering it through a designed planting soil media and collecting the flow through perforated under-drainage pipe work. Block paving Pre-cast concrete blocks used to construct a flexible modular paving system. Brownfield (site) Land which has already been built on in the past. Often, but necessarily, associated with land that is contaminated.

Bund A barrier, dam, or mound usually formed from earthworks material and used to contain or exclude water (or other liquids). Catchment A defined area, often determined by topographic features or land use, from which rain will contribute to runoff to a particular point. Catchpit A small chamber incorporating to trap sediment and other debris through which runoff passes. Chemical oxygen demand (COD) The measure of the amount of oxygen taken up by chemical oxidation of all oxidisable substances in the liquid sample. Used as a water quality indicator. Climate change Changes in meteorological conditions caused by the enhanced Greenhouse Effect, which is predicted to result in, amongst others, sea level rise and increased rainfall intensities. Coliform Bacteria found in the intestines, faeces, nutrient rich waters, soil, and decaying plant matter. Commonly used as an indicator for the existence of pathogens. Computer model A series of mathematical equations in a computer developed and used with the aim of replicating the behaviour of a system to enable prediction of the system performance for a range of conditions. Consent Permission (usually conditional) granted by the appropriate public authority; usually associated with the discharge of flow, or potentially polluting flow, to a watercourse or into the ground. Contaminated ground Ground that has the presence of such substances, which are present in sufficient concentrations, are likely to have detrimental effects if mobilised by the use of infiltration or other activity which disturbs their current state. Contributing area The area that contributes storm runoff or other output to the receiving system. Control structure Structure to control the volume or rate of flow of water through or over it. Conventional drainage The traditional method of draining surface water using open channels, subsurface pipes and storage tanks Conveyance The ability of a drainage feature to pass water from one location to another Critical duration event The duration of rainfall event likely to cause the highest peak flow, or largest volume, or cause the highest water level at a particular location, for a specified return period event Curtilage Land area within property boundaries Degradation The process of breaking down matter to a less complex state, usually by biological processes Deposition Laying down of matter via a natural gravitational process Design criteria A set of standards agreed by the developer, planners, and regulators a the proposed system should satisfy. Design storm A synthetic rainfall event of a specific profile, intensity and duration for a given duration and return period; derived by statistically analysis of a recorded historical series of rainfall events for a specific location. Detention basin A vegetated depression, normally dry, constructed to store surface water temporarily during periods of rainfall to



attenuate flows and provide some treatment and possibly infiltration. Detention pond Ponds similar to Retention ponds, but specifically distinguished (in Scotland) to have a smaller permanent pool volume which is sized to provide a treatment volume of 1 times Vt. Used where the risk of serious polluting incidents is considered to be low Diffuse pollution Pollution arising from land-use activities (urban and rural) that is spread widely across a catchment. Although surface runoff is discharged at discrete points, this is generally associated with diffuse pollution. Discharge The flow rate of liquid passing through a conduit. Discharge consent Permission to discharge surface water or effluent, subject to conditions laid down by a Regulator. Dissolved oxygen (DO) The amount of oxygen dissolved in water, used as an indicator of the health of a body of water for supporting the ecosystem. Down pipes Pipes leading down from roof guttering to the ground. Drainage A collection of conveyance and storage components, including pipes, channels and other engineered works (SUDS) designed to cater stormwater in a built-up environment. Duration The time period over which an event occurs or has an impact. Ecology All living things, such as trees, flowering plants, insects, birds and mammals, and the habitats in which they live. Ecology The relationship of all organisms with each other and their environment. Ecosystem A biological community of interacting organisms and their physical environment. Environment All physical and biological components (air, land, water resources, plant, and animal life) and their interaction of an area at any scale. Environmental Impact An assessment on the (potential) impacts of an activity or development, plan or policy. Normally associated with consideration of assessment of measures to mitigate the impacts; usually presented as an Environmental Impact Statement. Erosion The natural processes of weathering, dissolution, abrasion, corrosion, and transportation, by which solid material is worn away at a location and deposited elsewhere, usually by wind or water. Estuary A semi-enclosed body of water, usually the mouth of a river, in which seawater is substantially diluted with freshwater and where water levels are a function of both river flows and tidal influence. Evapotranspiration The process by which soil loses moisture by evaporation and by uptake and then transpiration from plants. Event (rainfall) Single occurrence of a rainfall period before and after which there is a sufficient dry period for runoff and discharge from the drainage system to cease. Extended Detention Basin A detention basin where the runoff is stored beyond the time required for attenuation of flow (flood control). The extra time allows greater removal of pollutants in the water. Extended detention basins still aim to drain down within 24 to 48 hours. Issues of vegetation health in the bed of the basin which is saturated for long periods needs to be considered. Practicalities associated with robust

performance of the hydraulic control structure may be a limiting aspect. Extreme event Single occurrence of an event that is likely to occur very infrequently (e.g. long drought or big storm). Fauna The animals found in a particular physical environment. Filter drain A linear drain consisting of a trench filled with a permeable material, usually gravel, often with a perforated pipe in the base of the trench to assist drainage. Filter strip Gentle uniformly sloping vegetated area designed to drain surface runoff as sheet flow from impermeable surfaces and remove sediment. Filtration In storm water treatment; a common process that removes particulate matter by separating water from solid material usually by passing it through media such as sand, gravel or dense vegetation. Fines Small soil particles less than 63 micron in size. First flush The initial discharge of surface water in which sediments and pollutants is of a higher concentration than average. Flood frequency The probability of a flow rate being exceeded in any year. Flood Risk Assessment Technical review of the risk of flooding, to or on a development, and on adjacent sites upstream and downstream. Flood routeing Consideration of ground level topography that act as pathways to minimise the adverse effect of flooding when the design capacity of the drainage system has been exceeded or has failed. Floodplain Land adjacent to a watercourse that is subject to frequent flooding under natural conditions due to periods of extreme rainfall. Flooding may be prevented due to intervention (constructed embankments), but the area so protected is still referred to as the floodplain. Flora The plants found in a particular environment. Flow control device A device used for the control of surface water, e.g. a weir. Flow regime The variation of discharge of a waterway usually over an annual or seasonal period. Fluvial flooding Flooding from rivers. Forebay Entry area for inlets of a basin or pond that is specifically designed to trap incoming coarse sediments to facilitate the operational management of the whole system. Foul drainage The infrastructure that drains domestic and commercial effluent. Freeboard Distance between the design top water level and the top of a structure; provided as a precautionary safety measure against system failure and to cater for wave effects. Frequency The number of occurrences of a certain phenomenon per unit time. Geocellular structure A plastic box structure used in the ground, often to attenuate runoff. Geogrid Plastic grid structure used to increase the bearing strength of soils or aggregates.



Geomembrane An impermeable plastic sheet, typically manufactured from polypropylene, high density polyethylene or other geosynthetic material. Geotextile A plastic fabric that is permeable. Good ecological status The values of the biological quality elements for the surface water body type show low levels of distortion resulting from human activity, but deviate only slightly from those normally associated with the surface water body type under undisturbed conditions. The classification of ecological status of surface waters is based on indicators chosen from the main biological groupings within an eco-system: aquatic flora, macro-invertebrate fauna and fish fauna. Taken together with hydromorphological and physico-chemical parameters, the overall ecological status of the river, lake, estuary or coastal water would be defined. Good groundwater status The status achieved by a groundwater body when both its quantitative status and its chemical status are at least "good". Good surface water status The status achieved by a surface water body when both its ecological and chemical status are at least ‘good’. It is based on biological, hydro-morphological and physiochemical elements. Gradient The angle of inclination of conduit or ground topography; influences flow velocity and system capacity. Green roof A roof with plants growing on its surface, which contributes to local biodiversity. The vegetated surface provides a degree of retention, attenuation and treatment of rainwater, and promotes evapotranspiration. Greenfield Land that has never been developed, other than for agricultural or recreational use. Greenfield runoff The runoff rate and volume from a site prior to development. Greenfield Site New development on land which has not been previously developed, usually at the periphery of existing urban areas. This creates increased rainfall-runoff and has a hydraulic impact on watercourses. Greywater Waste water from baths, showers, sinks (kitchen sinks are excluded due to nutrient rich effluent), and domestic appliances before it reaches the sewer. Groundwater protection zone Areas that influence water supply boreholes where groundwater must be protected from pollution. These are defined by reference to travel times of pollutants within the groundwater. Groundwater All water which is below the surface of the ground in the saturation zone and in direct contact with the ground or subsoil, i.e. below the water table. Gully A structure, usually associated with roads, to permit the entry of surface runoff into the drainage system. It is usually fitted with a grating and a grit trap. Habitat The area or environment where the particular conditions are suited to the existence of an organism or ecological community Head-discharge The relationship between a discharge rate and the water level causing that discharge. Hydraulic Control Unit A hydraulic device to control the rate of the flow. Hydraulics Hydraulics is another term for fluid mechanics used in the context of water engineering, and is the study of flows. In the context of SUDS, hydraulics covers the storage, conveyance and control of flows by the drainage network.

Hydrogeology Hydrogeology is the study of water below the ground surface and geological aspects of surface water. Hydrograph A graph showing, for a given point on a stream or conduit, the discharge, stage, velocity, available power, or other property of water with respect to time. Hydrological regime The quantity and dynamics of flow, and the connection to groundwaters. Hydrology The study of water, its properties, distribution and utilisation, from when it rains until it returns to the sea. Hydromorphological Hydromorphological elements relate to both the hydrological regime and the morphological conditions for a water body, be it a river, transitional water, coastal water, lake or heavily modified or artificial waterbody. Hyetograph Temporal intensity profile of a rainfall event. Impermeable surface Surface which resists the passage or infiltration of water. Impervious surface Surface which resists the passage or infiltration of water or any object or material Industrial hot spot Often used to denote an area where land use or activities have generated or generates pollutants which cause the runoff to be highly contaminated. Infiltration (a) The unintended ingress of groundwater into a (piped) drainage system. (b) The process of rainwater runoff passing into the ground. Infiltration basin A basin, which is normally dry, that is designed to store and infiltrate surface runoff into the ground. In order that Infiltration basins work correctly, the ground should comprise fairly pervious soils and management of the basin usually requires scarifying to maintain reasonable infiltration rates. Consideration of the sediment concentration of the influent is important. Infiltration trench A trench, usually filled with permeable granular material, designed to promote infiltration of surface water to the ground. Initial rainfall loss In hydrology, the rainfall needed to “wet” the catchment prior to surface runoff taking place. It includes interception, surface wetting, and filling of depressions. In-property storage Storage of rainfall within the curtilage of the property, e.g. in the gutter, roof space or chamber. Intensity-duration-frequency The relationship between rainfall intensity (amount per unit of time), rainfall duration (total time over which rainfall occurs) and frequency (return interval) at which the specific intensity-duration relationship is expected to recur. Interception The process by which rainfall may be prevented from reaching the ground or the drainage system, for example vegetation. Interception storage Provision of storage to prevent runoff from the site from small rainfall events, in order to replicate the site response to greenfield conditions. Interflow The horizontal passage of water through the soil, from where it may infiltrate vertically to an aquifer, move horizontally to a watercourse, or be evaporated. Interim Code of Practice (SUDS) An agreed interim position statement between various the UK stakeholders involved with drainage on the status and application of SUDS. (see References or CIRIA web site link)



Joint probability The probability of an outcome occurring due to the combined influence of two hydrological phenomena. The two phenomena may have some degree of dependency. Land use Catchments or development areas zoned based on economic, geographic or demographic use of land, such as residential, industrial, farm, commercial. Level of Service The design or actual performance of a system e.g. drainage network or flood defence, normally expressed in terms of the frequency of flooding experienced. Linear ponds An alternative to swales in serving runoff from roadways and hard standings. They are vegetated open channels that provide storage, conveyance and some treatment. They are particularly useful in flat terrain due to their hydraulic conveyance capability. Long Term Storage Storage of stormwater which is normally drained by infiltration that specifically addresses the additional volume of runoff caused by the development compared to greenfield runoff. The objective is to minimise any increase in flooding in the river downstream. Management train The management of runoff through the site using a range of SUDS techniques to maximise the hydraulic and water quality treatment benefits. Mean High Water The average tidal level of all high waters observed over a long period. Mean High Water Springs (Also known as Spring High Water) The average height of the high waters of the spring tides. Spring tides are those tides of increased range occurring bi-monthly as the result of the gravitational effect of the moon. Mean Sea Level The average level of the sea over a long period, or the level which would exist in the absence of tides. Micropool Pool at the inlet or outlet to a pond or wetland that is permanently wet and improves the pollutant removal effectiveness of the system. Mini Swale Small, grass-lined, channels designed to store and treat runoff from small rainfall events and, when larger events occur, discharge excess water directly into a supporting pipe drainage network. Morphology The hydrological and physical characteristics of a river. Network The whole (drainage) system of inter-connecting conveyance and storage structures, usually the term used in the context of a computer model of the system Non-return valve A pipe fitting that allows flow in one direction only. Numerical Modelling The use of computer models to replicate the behaviour of natural and manmade systems to assist in assessing their performance under a range of possible conditions. Nutrient A substance providing nourishment for living organisms (such as nitrogen and phosphorus). Off-line A structure is said to be off-line when it comes into operation only once the maximum “load” in the normal operational state of the system at a location is exceeded. On-line A structure is said to be on-line when it is in operation at all times under all “loads”. Open Water Clear water surface ie free from submerged or floating aquatic vegetation. Organic Naturally occurring compounds of carbon combined with

one or more other elements, most often hydrogen, oxygen, nitrogen, sulphur and halogens such as phosphorous, fluorine and bromine. Organic pollution A general term describing the type pollution that is biodegradeable. The effects of organic pollution are described by the levels of bio-chemical oxygen demand, ammonia, and dissolved oxygen found in a waterbody . Orifice A hole, usually round and specifically sized, often used to control the rate of flow. Outfall The point, location or structure where wastewater or drainage discharges from a pipe, channel, sewer, drain, or other conduit. Overflow The flow of excess water from a structure when the capacity of that structure is exceeded. Overland flow The flow of water over the surface from rainfall runoff before it enters some defined channel or inlet, or from excess flow passing out of a drainage structure that is full. Pathogen An organism that causes disease. Pathway The route taken by overland flow or other object in transit. Pavement Technical name for the road or car park surface and underlying structure, usually asphalt, concrete, or blockpaving. Note the path next to the road for pedestrians (colloquial term of pavement) is the footway. Peak discharge The maximum flow rate at a point in time at a specific location resulting from a given storm condition. Percentage runoff The percentage of the rainfall falling on a specified area which provides runoff (which enters the stormwater drainage system). Percolation The process of water passing (or other liquid) through a porous substance (eg soil or geotextile fabric). Permeability A measure of the ease with which a fluid can flow through a permeable medium. It depends on the physical properties of the medium, for example grain size, porosity, and pore shape. Permeable pavement A permeable surface that is paved and drains through voids between solid parts of the pavement into a permeable sub-base. Permeable surface A surface that is formed of material that is itself impervious to water but, by virtue of voids formed through the surface, allows infiltration of water to the sub-base through the inter-connecting voids. Pervious pavement Another term for permeable pavement. A permeable hardstanding designed to promote infiltration of surface runoff into a permeable sub-base. Pervious surface A surface that allows inflow of rainwater into the underlying construction or soil. Pesticide A general term for any chemical agent used in order to kill unwanted plants (weeds), animal pests or disease causing fungi. Phreatic surface Groundwater surface Piped system Conduits, usually round, generally located below ground to conduct effluent or other liquids to a suitable location for treatment and/or disposal.



Point source pollution Pollution that arises from an easily identifiable source, e.g. a WwTW outfall. Pollutant A contaminant whose concentration has increased to an objectionable level and which may cause harm to flora or fauna. Pollution The addition of a pollutant to the environment (a natural body of water) which diminishes the physical, chemical, radiological, or biological quality of a resource (air, water or land) and may have a negative impact on flora and fauna. Pond Depression of any size with a permanent pool of water, usually with ecological value. Poor status(1) Waters which show evidence of major alterations to the values of the biological quality elements for the surface water body type and in which the relevant biological communities deviate substantially from those normally associated with the surface water body type under undisturbed conditions. Porosity The percentage of the bulk volume of a rock or soil that is occupied by voids, whether isolated or connected. Porous asphalt An asphalt material used to make pavement layers pervious, with open voids to allow water to pass through (previously known as pervious macadam). Porous paving A permeable surface that drains through voids that are integral to the pavement. Porous surface A surface that infiltrates water to the sub-base across the entire surface of the material forming the surface, for example grass and gravel surfaces, porous concrete and porous asphalt. Priority substances Key substances, usually pollutants, identified by legislation as being critical to control from causing an impact on the environment. Probability The estimated likelihood of a storm event e.g. a 1 in 100 year flood event is one that is expected to be equalled or exceeded once every 100 years; it also has a 1% chance of occurring in any one year. Public sewer A sewer that is vested and maintained by the responsible public authority. Rainfall event A single occurrence of rainfall before and after which there is a dry period that is sufficient to allow the drainage system to return to, or near to, its steady state. Rainfall intensity Amount of rainfall occurring in a (short) period of time, generally expressed in mm/hr. Rainfall ratio “r” The ratio of depths for a 5 year return period event of 60 minute duration and a 5 year return period event of 2 days duration. Rainwater butt Small scale garden water storage device which collects rainwater from the roof via the down-pipe. Rainwater harvesting or rainwater use system A system that collects rainwater locally (usually from roofs, but occasionally from hard standings) rather than allowing it pass to the drainage system. Rational Method A simple drainage analysis method, used throughout the world, for calculating the peak discharge in a drainage system for pipe sizing. Receiving waters Water body (river or lake) which receives flow from point or non-point sources.

Recharge The addition of water to the groundwater system by natural or artificial processes. Reed bed Area of grass-like marsh plants, in or adjacent to water bodies. Artificially constructed reed beds are used to treat small volumes of the liquid component of sewage effluent. Regulator An organisation, usually government body, with the authority to stipulate requirements such as consents for discharges to receiving waters. Residential access roads These roads link dwellings and their associated parking areas and common open spaces to distributor roads. Retention Pond A SUDS pond consisting of a significant sized permanent pool of water (up to 4 times Vt) designed to treat surface runoff by detaining the water to provide settling of sediments, and chemical and biological processing as well as provide attenuation. Often used to provide high amenity value. Return period The reciprocal of the average annual probability of exceedence of a specific flow value or event. Risk Risk is a measure of the combination of the likelihood of an event (hazard probability) and the severity of the outcome (consequence). Risk assessment An evaluation of all the relevant risks (hazards and consequences) to enable appropriate actions or mitigating solutions to be devised. River Basin The area of land from which all surface run-off flows through a sequence of streams, rivers and, possibly, lakes into the sea at a single river mouth, estuary or delta. Runoff Water from precipitation which flows over surfaces and contributes to flows in a drain, sewer or receiving water. Runoff coefficient The proportion of total rainfall that appears as total runoff volume after subtracting losses, such as depression storage, infiltration and interception. Salmonid Waters High quality waters suitable for self sustaining populations of wild salmon and trout. Scour Localised erosion. Sediment Organic or inorganic material that has been transported by water, which has been deposited. Separate sewer A sewer for surface water or foul sewage, but not a combination of both. Separate Sewer System System whereby, foul sewage and stormwater run-off are kept separate and confined to individual designated sewer systems: one for foul sewage which is conveyed to treatment; and one for stormwater run-off which is discharged to water courses. Sewer A pipe or channel taking domestic foul and/or surface water from buildings and associated paths and hard-standings from two or more curtilages and having a proper outfall. Sewerage System of pipes (sewers) to transport sewage. Silt The generic term for waterborne particles with a grain size of 4-63 mm, i.e. between clay and sand. Simulation The representation of specific conditions during a specific period in a sewerage system, treatment works, river, etc., by means of a computer model. Site Control A term used in SUDS to denote drainage elements that are suitable for use in storm water management to



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maximise quality and quantity benefits for a small development or site. Soakaway A pit, usually filled by single sized aggregate, into which surface water is drained to infiltrate into the ground. Soil The terrestrial medium on which many organisms depend, which is a mixture of minerals (produced by chemical, physical and biological weathering of rocks), organic matter, and water. It often has high populations of bacteria, fungi, and animals such as earthworms. Soil Moisture Deficit (SMD) A measure of soil wetness, calculated by the Meteorological Office in the UK, to indicate the capacity of the soil to absorb rainfall. Source control Practices which manage runoff at or near its source. Source-Pathway-Receptor Model A method for establishing, assessing and communicating risk relationships. Standard Swale A grass-lined channel designed to convey surface water, as well as controlling and treating the flow. Storage The impounding of water, either on the surface or in underground chambers. Storm A natural occurrence which normally includes precipitation such as rainfall, snow, or hail. Stormwater The product of a meteorological event, often of rainfall, snow or hail, which forms runoff from surfaces which have an inability to infiltrate. Sub-catchment A division of a catchment, either for reasons of different land use, or for defining the extent of the contributing area to a drainage location. Sustainable (Urban) Drainage Systems (SUDS) Sustainable drainage systems: a sequence of conveyance systems and control structures designed to manage the drainage of surface water more sustainably than conventional techniques by providing treatment and reducing flow rates and volumes. Sump A pit that may be lined or unlined and is used to collect water and sediments before being pumped out. Surface water Water from precipitation which has not seeped into the ground and which is discharged to the drainage system. Surface Water Status The general expression of the status of a body of surface water, determined by the poorer of its ecological and it chemical status. Suspended solids Small particles that are carried in suspension in the water column and create turbid, or cloudy conditions. Often used as a simple indicator of the water quality of the water and also closely correlated with concentrations of some other relevant pollutants. Swale The term given to a grass channel for stormwater collection with shallow side slopes and gradients to allow ease of maintenance and which is normally dry except during rainfall. The design of the soil and vegetation is important to maximise its operational effectiveness, both hydraulically and for treatment. Temporary storage Storage of the excess water for high intensity events, where the drainage system is temporarily overloaded. Time of entry Time taken for rainwater to reach an inlet into the drainage system after hitting the ground. Often used in conjunction with design using the Rational Method. Time series rainfall A continuous or discontinuous record of individual events

generated artificially (stochastically) or selected from real historical events which is representative of the rainfall in that area. Toxic material Capable of producing an adverse effect in a biological system causing serious injury or causing death. e.g. pesticides and heavy metals. Trash rack Rack of bars installed to trap litter or debris to collect or to minimise risk of blockage in the system downstream. Treatment Improving the quality of water by physical, chemical and/or biological means. Treatment storage Storage provided to provide partial water quality treatment to surface water, primarily through sedimentation. Treatment train A series of SUDS components, each designated to treat a different aspect of runoff that are implemented together to maximise their effectiveness. Treatment Volume The volume of water provided in a pond to provide dilution and detention to inflowing surface runoff to provide partial treatment. Turbidity Reduced transparency of a liquid caused by the presence of un-dissolved matter. Unconfined aquifer An aquifer which is not overlain by an impermeable stratum. Under-drained Swale A swale where water percolates down through the base of the swale into a perforated pipe that collects and then discharges the flow to another part of the drainage system or the receiving waters. The swale may be a conveyance unit (where the under-drainage is aimed at ensuring well drained conditions in the bottom of the swale), or be designed only to provide temporary storage for the percolation process. Underground storage Underground structure, often constructed using concrete, grp, steel tanks or plastic void formers. They provide hydraulic attenuation, but do not treat the runoff. Urban drainage Drainage conveyance, storage elements and ancillary structures (pumping stations etc) to serve the urban environment. Vortex flow control The induction of a spiral/vortex flow of water in a chamber used to control or restrict flow. Wash off (of pollutants) The transport of pollutant mass from a surface during a rainfall event. Waste Any substance or object that the holder discards, intends to discard, or is required to discard. Disposal of waste, particularly Hazardous waste, is controlled by legislation. Water butt Small tank, usually covered and placed at ground level, connected to a down-pipe, to provide storage of water of runoff from roofs. Water quality The chemical and biological content of water, usually compared to defined standards, set by the national legislation or European Community Directives and enforced by regulatory authorities in member states. Water Quality Treatment volume The volume of water provided in a pond to provide dilution and detention to inflowing surface runoff to provide partial treatment. Water table The level where the surface of groundwater of an unconfined aquifer can be detected. The water table level fluctuates with the seasons and the annual rainfall and the demand on it made by man.



Watercourse A natural or artificial channel (rivers, streams, ditches) for conveying water Weir A hydraulic structure, usually horizontal, of a predetermined height and length to control the flow of water. Wetland A continuously wet area in which the water is shallow enough to enable the growth of bottom-rooted plants. It has a requirement for a continuous base flow to maintain healthy vegetation. Treatment of stormwater can be very effective, but if used for attenuation, consideration needs to be given to the effect of fluctuating water levels on plant life. Whole life cost The present day value of total costs of a structure throughout its likely operating life (construction, operation, decommissioning).



Selected References

1. Goyen, Allan. Spatial and Temporal Effects on Urban Rainfall/Runoff Modelling, University of Technology, Faculty of Engineering, Sydney, A thesis submitted to the School of Graduate Studies in fulfilment of the requirements for the Degree of Doctor of Philosophy, April 2000.

2. Baharudin Bin Fauzi. A Study on Rainfall – Runoff Characteristics of Urban Catchment of Sungai Kerayong, Thesis submitted in fulfilment of the requirements for the degree of Master of Science, JULY 2007.

3. Thorndahl, S. and Schaarup-Jensen, K. Comparative analysis of uncertainties in urban surface runoff modelling, Aalborg University, Department of Civil Engineering,Denmark.

4. Low Impact Development for Big Box Retailers, Prepared By: The Low Impact Development Center, Inc. Maryland.

5. Stormwater Management Study Arthur Capper/Carrollsburg Dwellings LID Project, March 2003, Prepared by: Department of Environmental Programs Metropolitan Washington Council of Governments Washington, D.C.

6. Low-Impact Development Hydrologic Analysis, Prepared by: Programs and Planning Division, Department of Environmental Resources, July 1999, Maryland.

7. Low-Impact Development Design Strategies, Prepared by: Programs and Planning Division, Department of Environmental Resources, July 1999, Maryland.

8. Lisa M. Powel l, Erica S. Rohr, Michael E. Canes, Jacqueline L. Cornet, Emil J. Dzuray, Lindsey M. McDougle. Low-Impact Development Strategies and Tools for Local Governments, September 2005.

9. Beven, Keith.J. Rainfall – Runoff Modelling: The Primer, Published by John Wiley & Sons Ltd. 2000, UK. 10. Biswas, Asit.K. Systems Approach to Water Management, Published by McGraw-Hill, Inc 1976, USA. 11. Singh. V.P. Rainfall Runoff Relationship, Proceedings of the International Symposium on Rainfall-Runoff

Modelling held in May 18-21, 1981, Mississippi State University, Mississippi, USA, 12. Singh. Vivekanand , Soni.B, Om Prakash. Urban Hydrology A state of the art – Report, National Institute of

Hydrology,2000-2001, Jalvigyan Bhavan, Roorkee, Uttaranchal. 13. Patel, Amit. Stormwater Management and Modeling – a case of Western Part of Ahmedabad, School of Planning,

CEPT University. 14. Dietz, Michael. E. Low Impact Development Practices : A Review of Current Research and Recommendations for

Future Directions, Published online September 2007 – Springer Science. 15. Trowsdale S.A, Elliott A.H. A Review of models for low impact urban stormwater drainage, Published online

March 2006 on ‘Science Direct’ by Elsevier publication. 16. Turner, Tom. Landscape Planning, Nichols Publishing Company, New York

Selected e-References

www.mrsc.org/.../apa/pss/news/200701vegswale.jpg http://eshop.macsales.com/green/images/water_bioswale.jpg ftp://ftp-fc.sc.egov.usda.gov/IA/news/BioswalesFS.pdf www.lowimpactdevelopment.org/.../tbm.htmlwww.ladstudios.com/.../Strategies_TreeWell.shtml www.bohlerengineering.com/LEED.html http://www.lid-stormwater.net/treeboxfilter_construct.htm http://www.unh.edu/erg/cstev/fact_sheets/tree_filter_fact_sheet_08.pdf www.chesterfield.gov/WorkArea http://bechtel.colorado.edu/~willam/4830%20Stormwater%20Design%20Presentation.pdf http://www.pwri.go.jp/team/pavement/ http://www.uee.kyoto-u.ac.jp/english/laboratory/geofront/ http://www.ladstudios.com/LADsites/Sustainability/Strategies/Strategies_TreeWell.shtml



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http://www.lowimpactdevelopment.org/school/other_prj/tbm.html�

http://www.bohlerengineering.com/LEED.html�

http://www.lid-stormwater.net/treeboxfilter_construct.htm�

http://www.unh.edu/erg/cstev/fact_sheets/tree_filter_fact_sheet_08.pdf�

http://bechtel.colorado.edu/~willam/4830%20Stormwater%20Design%20Presentation.pdf�

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indian space programme

space applications

space commission

application of space

major space systems

communication satellites

irs type of satellites

insat type of satellites