CE 3372 Water Systems Design

Module 002 – Brief History of Water and Wastewater Needs

Outline

• Brief History• Engineering and Design Concepts• Water Use and Control• Trenching

Brief History of Water Systems

• This brief history is adapted from – “Historical Urban Water Systems” by Dr. Robert

Pitt, Department of Civil and Environmental Engineering, University of Alabama, Tuscaloosa, AL 35487

• As we proceed through the history, consider whether the picture is a water control, water use, or environmental restoration system.

Brief History of Water Systems

• Drinking Water

Brief History of Water Systems

• Storm Water

Brief History of Water Systems

• Waste Water

Brief History of Water Systems

• Conduits

Brief History of Water Systems

• Pumps

Brief History of Water Systems

• Storage

Engineering

• “Engineering is the profession in which a knowledge of the mathematical and natural sciences gained by study, experience, and practice is applied with judgment to develop ways to use, economically, the materials and forces of nature for the benefit of mankind.”– NAP, 1985 “Engineering Education and Practice in

the United States: Engineering Technology Education” ISBN 0-309-07826-1

Engineering

• “Engineering is the profession where mathematical and natural science is applied to develop ways to use the materials and forces of nature to benefit mankind” – ABET is credited with this definition, yet the actual

quote is hard to find. The National Academies mentions ABET in the paragraph following their definition, so I will accept the above as ABET’s definition.

Engineering

• “Engineering is innovative application of knowledge to produce something to satisfy human needs”– Voland, G. 2004. “Engineering by Design” 2ed.

Prtentice Hall, 640p. ISBN 0131409190

Engineering

• Invention is neither necessary nor mentioned in the ABET definition. – engineering is systematic – science is systematic

• what are the 5 steps of the scientific method?

Engineering

• Invention is mentioned in the NAP definition but otherwise the definition is a lot like the ABET definition – Develop ways to … – Invent ways to …

Engineering

• Invention is the point of engineering in Voland’s definition – there is, in fact, no mention of systematic

• All three definitions serve the same customer (us!)– ABET: … to benefit mankind – NAP: … for the benefit of mankind– Voland: … to satisfy human needs

Design

• Creation of a solution to a problem– In a practical sense a design might be

• A drawing• A prototype• A report• A program• A set of instructions (recipe)

– Something from nothing that solves a problem

Design

• Things engineers “do” that are “design”– Select of specifications from a manual– Scheduling materials– Populating an input file to run a computer

program– Running a program to produce output to support

a permit application– Writing an operations protocol (a recipe to run

something)

Design

• Design is the management of constraints– Negotiable

• Money• Time• Aesthetics• Performance

– Non-negotiable• Physics• Chemistry

Design Constraints

• Identify and classify constraints• Manipulate design variables to satisfy non-

negotiable constraints and optimize negotiable constraints

Frequency Based Design

• Design to accommodate an event of some pre-determined probability (return frequency).– Assume that more frequent events are also

accommodated.• You did frequency analysis in hydrology! • T-year event

Risk Based Design

• Design to accommodate some pre-determined expected net loss.– Expected loss is product of the probability of

failure and the cost of that failure.

• Design to minimize the sum of initial cost and expected loss

• You did elements of risk analysis in hydrology, namely the probability portion.

Critical-Event Design

• Design to accommodate largest anticipated event.– Applied for systems where consequences of

failure are huge (economically and/or politically)– Large dams, nuclear power plants

• Assumes the event is anticipated– Earthquake + Tunsami + Pump Failure combined

were not anticipated (actually they were, just no-one paid attention!)

Hydrologic Data

• Design uses hydrologic and geologic data and various analysis tools– USGS: topography, streamflow, computer programs– NRCS: soil maps, land use, computer programs– US EPA: rules, chemical properties, computer programs– NCDC: rainfall, snowfall, solar radiation– USBR: Western US water and energy supply– USACOE: Navigable waterways, computer programs– FHWA: design manuals, computer programs

Hydrologic Data

• Design uses hydrologic and geologic data and various analysis tools– TWDB: Funding (for cities and water districts)– TCEQ: Rules, guidelines, some data– TNRIS: Evaporation estimates, digital elevation models,

digital ortho-quadrant maps, false IR images, etc.– TxDOT: Design manuals, some data, computer programs– County: Rules, design manuals, some operate rainfall-

stage networks– Cities: Rules, design manuals

Hydrologic Data

• Design uses hydrologic and geologic data and various analysis tools– River authorities– Drainage districts– Flood control districts– Irrigation districts– Council of Governments (COGs)

Data

• Most data are NOT free– Agencies charge a fee for data, usually pretty

small.– NCDC is worst offender of taking the fee, then

providing the wrong data, so be sure you know what you want.

– A lot of useful data are currently free, but don’t get offended if in the future you expected to pay for it.

Water Control Systems

• Spatial and temporal distribution of surface runoff from rainfall events (drainage engineering)– Flood control– Storm water harvesting

• Capacity is based on AREA served– hydrology dominated designs

Water Use Systems

• Spatial and temporal distribution in support of human habitation– Water supply/treatment/distribution– Waste water collection/treatment/discharge

• Capacity is based on POPULATION served– hydraulic dominated designs

Environmental Restoration Systems

• Spatial and temporal distribution in support of non-human habitation– Create “desirable” conditions

“Desirable” <= Policy <= Value Judgment

Trenching

• Most water distribution and some water collection systems are placed underground.

• Trenching is usually the most efficient way to place systems underground.

Trench Terminology

Backfill Guidelines (Typical)

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Backfill Guidelines

• Use requirements of jurisdiction where project is located.

• Flowline (invert grade line) is where bedding placed.

• Flowline determined by hydraulics and hydrology requirements.