a comparison of two highly sophisticated integrated surface ......a comparison of two highly...

A comparison of two highly sophisticated integrated surface water - groundwater models for urban stormwater applicationsA comparison of two highly sophisticated integrated surface water - groundwater models for urban stormwater applications

Maria Loinaz, P.E., PhDFlorida Stormwater Association Winter Conference

December 7, 2017

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FSA Winter Conference 2017

URBAN HYDROLOGY STUDY SPATIAL SCALES

To consider:Necessary hydrologic and

hydraulic componentsBoundary conditionsComputational timesStudy budgets and schedules

Regional

Streets and Sewers

Sub-Basin


GENERAL MODELING APPROACHES

Lumped Parameters

PHYSICS-BASED

SPATIALLY DISTRIBUTED

INTEGRATED

Empirical Equations

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To simulate during flood conditions Capability of the primary and secondary system to drain basins. Contribution and duration of groundwater to the storm flow. Structure capacities and operations

CASE STUDY SITE: CITY OF CAPE CORAL

“Unprecedented rainfall in Southwest Florida caused major flooding less than two weeks ago, causing thoroughfares to flood, including Burnt Store Road. As Hurricane Irma approaches, residents living nearby are worried that Burnt Store Road may flood again. Burnt Store Road acts as an evacuation route, and if the impact of Irma brings more flooding, the route could become inaccessible.” (nbc-2.com, Sep 2017)


To simulate during drought conditions: Water use needs throughout the basin (irrigation supply). Optimization of water supply distribution control elevations, timing of

pumps and gate openings.

Possible alternatives to evaluate with the model: Impact of structure additions and modifications Change in structure operational protocols Canal conveyance improvements Basin storage changes Land use changes Water use management

CASE STUDY SITE: CITY OF CAPE CORAL


Physically-Based, Spatially Distributed, Integrated Surface Water – Groundwater. Applications in Florida and worldwide include: wetland restoration, water supply plans, well field protection

studies, stormwater master plans, flood mapping, hydraulic infrastructure design and optimization

MIKE SHE/MIKE 11 BY DHI

Graphics from MIKE SHE ManualMIKE By DHI, 2016


Until 2016, ICPR was a node – link model. Suited for short design storms,not long-term simulations.

Applications in urban storm system drainage designs. Now ICPR version 4 has 2D overland flow and groundwater that

exchanges with 1D model. And has better capabilities for long-termcontinuous simulations.

Interconnected Channel and Pond Routing (ICPR) Model, Streamline Technologies, Inc.

Graphics from ICPR4 User’s Manual and Technical ReferenceStreamline Technologies, Inc, 2016


Objectives: To test the limits of a widely used tools in Florida with potential for new applications. Integrating modeling approaches leads to a more comprehensive understating of interactive hydrological and hydraulic

processes (the way of the future is interdisciplinary). Questions:

Can ICPR4 be applied at the same scales as MIKE SHE/MIKE 11? Can it be used to quantify surface water – groundwater interactions? What are the benefits and limitations of both models and approaches?

Model Comparison: Representation of urban features Capabilities for simulating overland flow, infiltration, groundwater flow Surface water 1D hydraulics and hydraulic structures Surface water – groundwater interactions Model development and computational efficiencies Input/output data processing tools Accuracy of the output and model numerical stability

MODEL COMPARISON OVERVIEW


ICPR 1D Node – Links Saint-Venant Equations (energy eqn. or momentum) Nodes

Stage/Area Time/Stage Stage/Volume

Links Channel (cross sections – options for different geometry

types) Pipes Weirs (cross sections – options for different geometry types) Drop Structures Breach French Drains Rating Curves

Manual basins

SURFACE WATER HYDRAULICS

MIKE 11 – 1D Open Channel Flow Saint-Venant Equations (kinematic, diffuse or fully dynamic) Cross-sections – irregular geometry, add storage options Culverts Bridges Weirs Pumps (rating curves) Other types of customized options Dam break Str. Control Structures – (underflow, overflow, discharge).

Flexible logic-based operation module that allows controls based on several types of variables

Rainfall-runoff catchment options Now MIKE 1D includes both MIKE 11 and MOUSE (Urban

collection system, pressurized flow) into one engine.


OVERLAND FLOW

MIKE SHE 2D: Fixed square grid Finite difference

Diffusive wave equation (neglects inertial terms, but can produce backwater effects)

Manning’s n formulation – fixed with depth

Multi-cell overland flow method option

Paved area runoff option

Separated overland areas options

Reduced area option

New ponded drainage option

ICPR 2D: Triangular Mesh Finite volume – control volumes (honey combs)

Triangle vertices acts as nodes, sides are the links, and the individual honeycombs are the basins.

Multiple features can be used to define the mesh (e.g., breaklines, breakpoints, exclusions, weirs, etc.

Mass balance for control volumes: Qin = link in ± excess + external + seepage

Qout = link out + irrigation

1D momentum, energy or diffusive wave equation

Depth varying Manning’s n

Dampening threshold option

Area reduction factor option


ICPR Curve Number – used in traditional hydrological

models. Empirical formulation.

Green-Ampt – physically based.

Vertical Layers – same as the GA but discretized into multiple layers.

UNSATURATED (VADOSE) ZONE: INFILTRATION AND EVAPOTRANSPIRATION

MIKE SHE Richards Equation – computationally complex, but most

accurate. Suited for field scale applications with variable conditions.

Gravity Flow (simplified Richards Equation neglecting capillary effects).

2-Layer Water Balance with or without Green-Ampt infiltration


SATURATED GROUNDWATER FLOW

ICPR 2D groundwater flow – one aquifer layer with option

for leakage across a confining layer.

Finite element – six-point triangular element with a quadratic interpolation function developed by Martinez, 1989.

Triangular Mesh – aquifer properties (depths, porosities, conductivities, and leakage) can be spatially varied for each triangle.

Interacts with the vadose zone when using Green-Ampt, not the Curve Number method.

Overland flow is required when interaction with vadose zone or surface water.

Boundary features include: irrigation, injection wells, and drains

MIKE SHE 3D groundwater flow – multiple layers possible representing

confined and unconfined conditions.

Finite difference (solver similar to MODFLOW)

Fixed grid (same size as the overland flow grid) – aquifer properties can be spatially varied for each cell.

Drainage option – sub-surface routing for features that intercept the water table (e.g., agricultural ditches, exfiltration trenches)


SURFACE WATER – GROUNDWATER INTERACTIONS

MIKE SHE Overland flow – canals (MIKE 11)

Runoff: overland stage > canal bank Canal flooding: flood codes or weir formula

Groundwater flow – canals Two-way exchange based on head difference and

conductance MIKE SHE interpolates MIKE 11 geometry

ICPR Overland flow – 1D node/links part of 2D

overland flow features (channel control volumes, pond control volumes)

Groundwater – 1D node/links part of 2D overland flow features (channel control volumes, pond control volumes, French drains).


CLIMATE INPUTS AND BOUNDARY CONDITIONS

MIKE SHE Rainfall

Uniform in space and time Station based time series (NEXRAD grid or Thiessen

polygon map) Fully distributed

Reference ET Same as rainfall

Boundary Conditions Flow hydrographs Stage time-series Overland flow and groundwater boundaries can be user

defined head/flux or based on results from a larger model.

ICPR Rainfall

Predefined non-dimensional distributions. Distributed rainfall based on a map, such as a

NEXRAD grid. Reference ET

Distributed based on a map and time series data for each zone (satellite based data).

Boundary Conditions External hydrographs Time-Stage Overland and groundwater point, line, and area mesh

features for stage and external flow.


WATER USE AND WATER QUALITY

MIKE SHE Irrigation

Surface water, groundwater, or external sources User defined or calculated demand based on soil

moisture or evapotranspiration requirements. Pumping wells

Abstraction (irrigation or out of the model) or injection Located in any geological layer in the model.

Water Quality Advection-dispersion transport ECOLab: chemical/biological process module in all

major model components.

ICPR Irrigation

Surface water, groundwater, or external sources Irrigation rules based on moisture content or

antecedent rainfall Pumping wells

Irrigation or injection Water table aquifer

No Water Quality


MODEL AREA 1

Total area: 20,488 ac (32 sq. mi.) 8 Cape Coral drainage basins Divided into 36 sub-basins ~80 miles of canals 51 hydraulic structures

Culverts / Bridges (35) Fixed weirs (5) Operable gates (8) Inter-basin transfer pumps (3)

Potential evaluation alternatives: Predict areas prone to flooding and evaluate impacts of

changes in hydraulic infrastructure. Optimize storage of Basin 4. Prioritize structure modifications.


MODELING APPROACHES – MODEL AREA 1

Topography (ft-NAVD)

ICPR MIKE SHE 36 Nodes connected via pipes at sub-basin boundaries

(at canal constrictions – culverts/bridges) Pond control volume approach

200-foot grid Runoff generated via paved areas and drainage options

in urban areas and via overland flow in wetland areas


Total area: 2,408 ac (3.8 sq. mi.) Test features of both models ICPR

Channel links with actual cross-sections Channel control volume approach

MIKE SHE 50-foot cells

What information are we losing with simplifications made for the larger model area?

What are the implications for regional studies? Can we use this information to better parameterize

large area models?

MODEL AREA 2: TEST AREA


We are currently in the process of completing model development. ICPR

Complete model inputs and parameterization Overland flow mesh refinement – pond control volume approach versus channel control volume approach. Groundwater flow mesh – Automatic mesh generation produces too many triangles, which makes the . Working with ICPR4

developers to improve efficiency by modifying mesh features. MIKE SHE

Complete model inputs and parameterization Test overland flow features: new drainage routing option and multi-cell size option

Comparison of results will include: Model calibration

Groundwater elevations (2 locations) Surface water stages (4) and flow (3)

Water budgets at the basin scale Flooding predictions for different model areas

NEXT STEPS…


ADA Engineering, Inc.

Pete Singhofen, Streamline Technologies, Inc.

DHI

City of Cape Coral

ACKNOWLEDGEMENTS

Thank you

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