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Laurie Morgan, Hydrogeologist
Washington State Dept. of Ecology
Water Quality Program Presented to the GWPC October, 2014
https://fortress.wa.gov/ecy/publications/SummaryPages/1410005.html
Washington Ground Water Management Areas - Nitrate
Columbia
Basin
2001
Lower
Yakima
2011
Chapter 173-100 WAC – Ground Water
Management Areas and Programs
3. Weiser
Goals
Delineate areas where nitrates are high in groundwater
Prioritize those areas by impact to people and
resources
Make information available to everyone
Inputs
Database of nitrate sampling results for groundwater from state
and federal databases
USGS nitrate risk studies
GIS resources, such as soils, surficial geology, and irrigated areas
Select topographically distinct areas at high risk of groundwater
contamination by nitrate
Prepare project information, data and GIS layers for a future web
based map application
Delineate Nitrate Priority Areas
Prioritize using criteria developed with
partners (especially WDOH)
Loading Estimate Method
Hydrogeologic “Facts on a Map”
Strategy for Tracking Conditions and Trends
Web map deployment
No
w
Fo
r c
on
sid
era
tio
n
Richland
Bellingham
Pasco
Tacoma
Olympia
Vancouver
Seattle Spokane
Yakima
Walla Walla
Kennewick
Hanford
Urban
Crop Lands
Shellfish Beds
Tribal Lands
Olympic
Mountains
Blue
Mountains
Portland
Basin
Willapa
Hills
Columbia
Basin
Rocky
Mountains
Volcano
Mt Baker
Glacier
Peak
Mt Rainier
Mt Adams
Mt Saint
Helens
Mt Hood
Quaternary Terrace
Ringold
Dunes
Alluvial
Loess Glacial
Flood
Source: WA Dept. of Natural Resources,
Division of Geology & Earth Resources
Water Wells: 285,463
Resource Protection: 214,540
Abandoned Wells: 130,313
WA Dept. of Health: 16,327 well locations, 94,185 sample results, 2000 to 2011
USGS: 4,361 well locations, 9,215 sample results, 1970 to 2011
WA Dept. of Ecology: 2,963 well locations, 11,458 sample results, 1982 to 2012
Historical Max >= 10 mg/L Nitrate as N
Historical Max >= 5 & < 10 mg/L Nitrate as N
Historical Max >= 3 & < 5 mg/L Nitrate as N
Historical Max < 3 mg/L Nitrate as N
Wells with Nitrate Graph – 4 or more Samples, at least 1 >=5 mg/L Nitrate as N
Historical Max >= 10 mg/L Nitrate as N
Historical Max >= 5 & < 10 mg/L Nitrate as N
Graphed
Wells with Nitrate Graph – 4 or more Samples, at least 1 >=5 mg/L Nitrate as N
Historical Max >= 10 mg/L Nitrate as N
Historical Max >= 5 & < 10 mg/L Nitrate as N
Graphed
85’
2005
Grandview – Population ~ 11,000
Grandview
Historical Max >= 10 mg/L Nitrate as N
Historical Max >= 5 & < 10 mg/L Nitrate as N
Graphed
Grandview
Mabton
Blended
Historical Max >= 10 mg/L Nitrate as N
Historical Max >= 5 & < 10 mg/L Nitrate as N
Graphed
Wells with a Hyperlink – USGS and Washington Dept. of Ecology
Wells with a Hyperlink – USGS Well Information Page
Wells with a Hyperlink – Ecology Well Information Page
Historical Max >= 10 mg/L Nitrate as N
Historical Max >= 5 & < 10 mg/L Nitrate as N
Nitrate Probability Grid (Frans, 2008)
100
50
0
Percent Probability of
detecting elevated nitrate
concentrations in
groundwater*
Hanford
Tribal
* >= 2 mg/L at 145’ depth
below land surface Frans, L.M., 2008, Estimating the probability of elevated nitrate concentrations
in ground water in Washington State: U.S. Geological Survey Scientific
Investigations Report 2008–5025, 22 p. Online at
http://pubs.usgs.gov/sir/2008/5025/
Nitrate Probability Grid (Frans, 2008)
Frans, L.M., 2008, Estimating the probability of elevated nitrate concentrations
in ground water in Washington State: U.S. Geological Survey Scientific
Investigations Report 2008–5025, 22 p. Online at
http://pubs.usgs.gov/sir/2008/5025/
>= 50% for W. Washington
>= 70% for E. Washington
Nolan, Bernard and Hitt, K.J., 2006. Vulnerability of Shallow Groundwater And
Drinking-Water Wells to Nitrate in the United States, in Environmental Science
& Technology/Vol. 40, NO.24, pp. 7834-7840. Online at
http://water.usgs.gov/nawqa/nutrients/pubs/est_v40_no24/est_v40_no24.pdf
Nitrate Prediction Grid (Nolan, 2006)
>= 10 mg/L
>= 5 & < 10 mg/L
High N Application
High Water Input
Well-Drained Soils
High effective porosity soil/ fractured rock
Lack of attenuation processes
“As N loading at the land surface increases,
nitrate concentration in shallow groundwater
increases”
Hanford
Tribal
Excessively drained Somewhat excessively drained Well drained Moderately well drained Somewhat poorly drained Poorly drained Very poorly drained
SSURGO Soils Drainage Classes of Washington Most of Washington is “Well Drained”
Lands adjacent to Puget Sound are to a greater extent “Moderately Well Drained”
Very limited areas of poor drainage
Noticeable areas of excessive drainage, where water passes quickly through the soil profile
Excessively Draining Soils of Washington
Source: NRCS SSURGO Soil Data, Downloaded 2013. Background Imagery Bing
Hanford
Tribal
Excessively Draining
Somewhat Excessively Draining
Irrigated Agricultural Areas of Washington
Source: Washington State Dept. of Agriculture, Perry Beale, 2013. Background Imagery Bing
Hanford
Tribal
Washington Dairies
Background Imagery Bing
Green draft outline based on
sections
Review and make any changes
Refine line work based on
natural boundaries
Frans Nitrate
Probability Grid
Nolan Nitrate
Prediction Grid
Delineation Example – Royal Slope &
Mattawa, Columbia Basin
Mattawa
Nitrate Sampling Max 5 to
10 and >= 10 mg/L
50
55
60
65
70
75
80
85
90
95
100
Royal City
>= 10 mg/L >= 5 & < 10 mg/L
>= 10 mg/L >= 5 & < 10 mg/L
Use multiple lines of evidence
Historical nitrate sampling data
Risk grids
Soil conditions
Irrigation/precipitation
Presence of loading source
Hydrogeology/groundwater use
Bin areas
Highly likely
Moderately likely
Somewhat likely
After first draft areas are delineated, inventory the areas and categorize
Inventory areas – Quantify and Describe
Total wells sampled, percents over MCL
Percent area with high risk conditions (USGS)
Percent area with high risk soil conditions (such as excessive
drainage)
Irrigation/precipitation
Loading source areal estimates
Prioritize areas
Severity of contamination indicators
Population affected
Availability of clean water alternatives
Priority
Rank = Likelihood + Impact
Database errors
− Typos, locational
− Generally really good, but you must watch out for the occasional error.
− This is best done when working on a specific area as opposed to the entire state (limited checks)
Public Water Supply data
− Where the sample was taken – at the source or not
− Before or after treating/blending
− When did treatment/blending start
− Was the well abandoned – possibly due to nitrate contamination issues
All nitrate result data
− Well depth and construction
− Project purpose – at a specific nitrate source, or ambient?
− QA level – Nitrate is not as sensitive at higher levels (must follow sampling and lab protocols, important to keep sample cold)
− The data is always historical – some of it is relatively recent
Things that
matter
Things we can
control Bingo!
Hydrogeology
− Groundwater Web Atlas – Make hydrogeological information easy to
access. Compile information from various sources.
Fund projects
− Address needs that are well defined and based on physical reality on
the ground.
− Prioritize according to impacts on people’s drinking water.
Photo: Lyn Topinka (USGS) - http://vulcan.wr.usgs.gov/Imgs/Jpg/Rainier/Images/Rainier84_mount_rainier_and_tacoma_08-20-84.jpg [1]