Transcript Gil Strassberg

Susceptibility
Assessment for Public
Water Supply sources
Gil Strassberg
What is a Susceptibility Assessment?
The traditional risk assessment – Point effects an Area
Susceptibility Assessment – Area effects a Point
Point Source
Non Point Source
We can use the similar physical properties
for both assessments
Schematic Overview
PWS intake
Topo:
filled elevation
flow accumulation
flow direction
Shaded relief
Slope
Synthetic stream net
Soils
Watershed Delineation
Delineated
Watershed
nhd network
mrlc
Geological
Clim:
Precipitation Stations
Annual and seasonal precipitation
Annual and seasonal Discharge
Annual and seasonal Runoff
Annual and seasonal R/P ratio
Categories:
Ecological regions
hydrological categories
hydrological regions
hydrological units
official basins
Soil Type
multi regional land
coverage
Flow Direction
PSOC Coverage:
lpst
Population
Animal population
Highway network
Toxic release inventory sites
Water Quality
Monitoring Data
Length Zones
?
Business
rules
Chemical grouping
amd properties
Susceptibility assessment
Calculating Length Zones –Time Zones
Flow Direction Grid
Flow Length Grid
Using flow length function
in arc info workstation
Length Zones Coverage
Calculate new grid
with unique values
From grid
to coverage
Intersecting sources and length zones
Using select by location function
Zone
number
Petroleum
Storage
tanks
Toxic
release
inventory
1
0
0
2
0
0
3
11
2
4
0
0
5
0
0
6
0
0
The number of Sources in the Area
Relative location of the sources
Physical Model
Qin Co
Ce  Co  AF
Ce
 AF
Co
Qout Ce
Physical
Attenuation:
• Sorption
• Decay
• Volatilization
• Advection
• Dispersion
Summary
What do we know?
• Area that effects the intake and its properties.
• Number of sources in the area.
• Relative location of point and non point sources.
• Attenuation Factor in groundwater
Future Work?
• Refine attenuation factors for ground and
surface water.
• Apply the methodology on case studies.
• Compare to available water quality data.
Acknowledgments
• Dr. Maidment and Dr. Katz
• USGS: Randy Ulery
Richard Kiesling
Toby Welborn
• TNRCC – SWAP team
• Research Team at Pickle