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Development of DRAINWARMF Model to Simulate Water Flow

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Data module provides time series input data (meteorological, ... If time delay 1 day then delays the flow accordingly. 14. Study Area. St. Esprit Watershed ... – PowerPoint PPT presentation

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Title: Development of DRAINWARMF Model to Simulate Water Flow

1
Development of DRAIN-WARMF Model to Simulate
Water Flow Nitrogen Transport From an
Agricultural WatershedSubsurface Flow
Component

Shadi Dayyani
Shiv Prasher
Chandra Madramootoo
Ali Madani

McGill University Department of Bioresource Eng.
CSBE 2008 Annual International Meeting, July 14th
2
Main Goal

To develop and validate a model to quantify flow
and nitrogen transport from an agricultural
watershed
Objectives
Evaluate DRAINMOD WARMF (surface flow) models
individually for hydrology nitrogen transport
Develop a new model (DRAIN-WARMF) linking WARMF
DRAINMOD models to
Simulate water quantity and quality (Nitrogen)
on a watershed scale
Evaluate impact of Best Management Practices
(BMPs) in reducing pollution from the watershed

3
Surface Flow WARMF ModelWatershed Analysis Risk
Management Framework

Watershed scale model developed by Systech Water
Resources under sponsorship from Electric Power
Research Institute (EPRI).
Links GIS, data, and a modeling system together
in a graphical user interface (GUI).
The algorithms of WARMF were derived from many
well established codes
Strong point Surface flow component
Weak point Subsurface flow component

4
WARMF

Model Inputs
Meteorological data
Daily values for precipitation, Min/Max
temperature, Cloud cover, Dew point temperature,
Air pressure, Wind speed
Sub-basin shape file
ID, Area, Slop, Aspect
Land use shape file
Streams shape file
ID, Upstream sub-basin, Downstream River ID,
River Length / Slope / Width / Depth, Min/Max
Elevation
Model Outputs
Surface flow

Structure of WARMF
Organized into five linked modules
Engineering module is the dynamic, simulation
model that drives WARMF
Data module provides time series input data
(meteorological, point source) and calibration
data
Knowledge module is a utility to store important
documents for the watershed
Consensus TMDL modules are roadmaps that
provide guidance for stakeholders during the
decision making process

5
Subsurface Flow DRAINMOD

Field-scale computer simulation model developed
by Dr. Skaggs in 1980
The model simulates
Hydrology of poorly drained, high water table
soils
Nitrogen dynamics in the soil-water-plant system
under different management practices
Effects of drainage and water management
practices on water table depths, soil water
regime and crop yields
DRAINMOD includes freezing, thawing, and snowmelt
components

6
Development of the Model (DRAIN-WARMF)
Flowchart of the DRAIN-WARMF modeling interface
7
GIS (Geographic Information Systems)

Layers
Sub-basins
Drainage
Soil
Landuse
Nitrogen Application
DEM
Stream Network

8
WARMF Output Processor / DRAINMOD Input File
Creator

Inputs
Surface flow (each sub-basin)
Precipitation
Sub-basin layer
Outputs
(Depth of surface runoff)i
i sub-basins ID
(Rainfall)i Precipitation (Depth of surface
runoff)i
DRAINMOD Rainfall input files are created

9
DRAINMOD Input File Creator

Subdivides watershed into uniform cells
Derive DRAINMOD input parameters for each cell
Sub-basins (ID, Rainfall file)
Landuse (.cin file)
Soil (.sin, .mis, .wdv files K value)
Drainage
drained / un-drained
Drainage coefficient
Drain depth / spacing
DEM (elevation)
Creates .gen .prj files for each cell
Store DRAINMOD input parameters for each cell and
identify accompanying files (weather, cropping,
soils, and hydrology)
? Results in a full set of DRAINMOD input files
for each cell in the watershed

9
10
Run DRAINMOD/Output Processor

DRAINMOD simulations are run for all cells
The output processor
Reads DRAINMOD output files (.plt)
Subsurface flow depth WTD
For drained cells, drain outflow is calculated by
querying the subsurface flow depth from the .plt
file for each cell
For un-drained cells, the value of WTD is taken
from .plt file for each cell

11
Subsurface Flow CalculatorUn-drained cells

Finds the receiving cell for each un-drained cell
Using DEM and WTDs calculated by DRAINMOD
Calculates the WTHcell Elevationcell WTDcell
Takes the ?WTH (between the un-drained cell (a)
and 8 neighbor cells)
Find the Max (?WTH)
Set the subsurface flow direction to the steepest
down slope neighbor Max (?WTH)
cell a flows to cell 7
Calculates flow using Darcys law
Between cell a and 7

11
12
Subsurface Flow CalculatorUn-drained cells

X cell size
Darcys Law
Area
12
13
Watershed Subsurface Flow Calculator

2 ways
Not routed
Results from each cell are summed to provide the
total subsurface drainage flow for the entire
watershed
Routed
Using stream network (Network Analysis in GIS)
Calculates each cell distance to watershed outlet
through streams
Asks for average time of concentration the
longest path
Calculates time delay for each cell
If time delay gt 1 day then delays the flow
accordingly

14
Study AreaSt. Esprit Watershed

A sub-watershed of L'Assomption River in Quebec
Located 50 km northeast of Montreal
Consists of 18 sub-watersheds covers an area of
25 km2 agricultural land occupies 65 of the
total area
In the L'Assomption river basin, significant
portion of the pollutant load comes from
agricultural sources (Quebec Ministry of
Environment)

14
15
Preliminary Results (Flow Simulation)

Results Not routed

Daily total subsurface flow at outlet
Monthly total subsurface flow at outlet
15
16
Preliminary Results

Results Routed

Daily total subsurface flow at outlet
Monthly total subsurface flow at outlet
16
17
Summary

A comprehensive evaluation of WARMF model in
eastern Canada under cold condition
A comprehensive evaluation of DRAINMOD in eastern
Canada under cold condition considering both
drainage flow and water table depth
Development of a new model, DRAIN-WARMF, to
simulate water flow and nitrogen transport from
an agricultural watershed

18
Future Work