|
Laboratory for Spatial Analysis in
The
GeoSciences |
1. Groundwater Susceptibility Analysis
(GWSA) 2. Surface Water Susceptibility Analysis
(SWSA) 3. Rational Method Runoff Calculator
(RMRC) 4. Aquifer Probability Coverage (APC) 5. Groundwater Flow Model (GWFM) 6. Water Budget Analysis (WBA) September 2003 Prepared for: And Prepared by: Laboratory for Spatial Analysis in the
Geosciences (LSAG)
Executive
Summary
This
report summarized the results of an analysis of surface water and groundwater
in the Ten Mile Lake watershed and surrounding area. Included with this report are a group of
tools to aid the Ten Mile Lake Association and their cooperators in managing
water resources for land-use planning.
There are six major components: groundwater susceptibility analysis
(GWSA), surface water susceptibility analysis (SWSA), rational method runoff
calculator (RMRC), a 3D aquifer probability coverage (APC), Groundwater flow
model (GWFM), and a water budget for Ten Mile and Birch Lakes (WBA).
The GWSA is based upon a model of
aquifer sensitivity to ground water contamination from pollutants introduced at
or near the surface. The model was built
using DRASTIC: A standardized system for evaluating ground water pollution
potential using hydrogeologic settings.
Inputs to the DRASTIC model consist of seven parameters that define the
intrinsic characteristics of the hydrogeologic system including depth to water,
recharge, aquifer media, soils, topography, impact of vadose zone, and
hydraulic conductivity of the aquifer.
The model output consists of a grid coverage containing relative aquifer
sensitivity rankings for the Ten Mile Lake Watershed and surrounding area. The rankings are classified into four
categories of sensitivity: 1) low, 2) moderate, 3) high, and 4) very high based
on the results of the analysis.
The Surface Water Susceptibility
Analysis (SWSA) determines relative runoff potential based on inputs of
distance to water bodies (major rivers, lakes and streams), slope, land cover
and soil parameters.
The Rational Method Runoff
Calculator (RMRC) is an extension developed by UMD using Arcview Version
3.2. The purpose of RMRC is to calculate
the peak discharge (Q) utilizing the Rational Method from a user-defined
watershed. This is done in conjunction
with another extension named “Basin1” which uses digital elevation data to
derive watersheds based on a user-defined point.
The Aquifer Probability Coverage
is derived from the water well drillers logs housed in the Minnesota County
Well Index. Stratigraphic
The Groundwater Flow Model is a
numerical simulation of groundwater flow in the Ten Mile Lake Watershed and
surrounding area. The flow model was
developed using MODFLOW with GMS (Groundwater Modeling System) as the data pre
and post-processor. The model is a
steady-state representation of the groundwater system, which can be used to
determine flow direction, flow rates, and to delineate wellhead protection
areas.
The Water Budget Analysis is an
assessment of the hydrologic inputs and outputs to the Ten Mile and Birch Lake
Watersheds. The water budgets were
compiled on an annual basis for the years 2000, 2001, and 2002. The goal was to examine the magnitude of
water exchange between Tenmile and
Table of Contents
1.3 Water Resource Management Tools Definition and Purpose