Nitrate Priority Areas

Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator:
Laurie Morgan, Washington State Department of Ecology, Water Quality Program , Hydrogeologist
Publication_Date: 20170406
Title: SDE.SDE.Nitrate_Priority_Areas
Geospatial_Data_Presentation_Form: vector digital data
Description:
Abstract:
The Washington State Department of Ecology (Ecology) Water Quality Program undertook the Nitrate Prioritization Project in 2014 (Morgan, 2014) because of growing concerns about groundwater contamination by nitrates, and the inability to display and evaluate nitrate data on a statewide basis. This report originated from the agriculture and water quality talks that took place in 2012. Participating agencies agreed that if data exists, everyone should be able to see it in one central location. Agencies that contributed included the Washington Dept. of Ecology, Washington Dept. of Health, Washington Dept. of Agriculture, U.S. Environmental Protection Agency, U.S. Natural Resource Conservation Service, U.S. Geological Survey, and the Washington Conservation Commission. The Safe Drinking Water Act nitrate limit for delivery of water from public water systems is 10 mg/L. This limit has been exceeded in public water supplies and private wells in various areas of the state going back decades. Not only is contaminated groundwater a public health issue, treatment is also very costly to the public water supply systems and individual households who must deal with contamination on their own. The goals of this project were to: Collect and organize statewide information about nitrate monitoring results, the physical factors that tend toward nitrate contamination, and United States Geological Survey (USGS) risk studies that evaluate the physical factors against monitoring results. Delineate areas where high nitrates in groundwater occur. Prioritize those areas by potential impacts to people and resources. Make the information available to everyone. The inputs for developing candidate Nitrate Priority Areas include: A single database of nitrate sampling results for groundwater compiled from state and federal databases. USGS nitrate risk studies. Surficial geology, soil properties, topography, well locations and depths, agricultural land use, irrigated areas, annual average precipitation, nitrate concentrations, and population. Monitoring data from the USGS and the Washington State Departments of Health and Ecology were collected and summarized. The well locations were mapped using a Geographic Information System (GIS). Clusters of wells where a sample has exceeded 10 mg/L are a strong indicator that groundwater at that location is at high risk of, or currently is contaminated by nitrate. Other indicators include USGS nitrate risk analyses, Natural Resources Conservation Service (NRCS) soil drainage classes and travel time through the soil profile (Ksat), surficial geology, recharge and well depths.Boundaries for candidate Nitrate Priority Areas were developed based on section lines that approximate natural boundaries. These areas will be subject to review and change where appropriate. Once the proposed Nitrate Priority Areas have been reviewed, section line-based boundaries may be replaced by natural boundaries where appropriate. Time series plots were produced for wells with four or more sample results with at least one result over 5 mg/L. This resulted in a distribution of over 1200 graphs across the state. These are accessible through the GIS as a popup from the well location point for those who have a GIS system with this capability, and who request and receive the necessary files. A web-based application would make these graphs widely and easily available. Challenges with databases always include checking for errors, such as the occasional locational or data entry error. Care must be used to understand the limitations of the data and the peculiarities of each data source. These issues are described more in this report. Recommendations include developing a web application to make this information easily accessible by anyone with internet access, and automating the data downloads so they are easily updated. Management of nitrate sources to prevent groundwater contamination should be adjusted for sensitive conditions like excessively draining soils and very hydrologically conductive geologic materials. Nitrate source loading needs to be reduced in impacted areas to prevent groundwater contamination. Results of this study can be used to protect public drinking water supplies by focusing actions on areas within the state that have the highest potential for impacts due to nitrate contamination of groundwater.
Purpose:
In order to delineate areas where high nitrates in groundwater occur, Ecology used monitoring data, USGS nitrate risk studies, and landscape patterns of contributing factors to nitrate contamination. Ecology then drafted initial boundaries to consider for Nitrate Priority Areas based on the evidence and topography. Areas were then inventoried for metrics to be used for prioritization. See Washington Nitrate Prioritization report at https://fortress.wa.gov/ecy/publications/documents/1610011.pdf for more information.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20160531
Currentness_Reference: Washington State
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -124.323915
East_Bounding_Coordinate: -116.870651
North_Bounding_Coordinate: 49.019458
South_Bounding_Coordinate: 45.500564
Keywords:
Theme:
Theme_Keyword_Thesaurus: None
Theme_Keyword: groundwater
Theme_Keyword: nitrate
Access_Constraints: None
Use_Constraints: None
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Washington State Department of Ecology, Water Quality Program
Contact_Person: Laurie Morgan
Contact_Position: Hydrogeologist
Contact_Address:
Address_Type: mailing
Address: PO Box 47600
City: Olympia
State_or_Province: Washington
Postal_Code: 98504-7600
Country: US
Contact_Voice_Telephone: (360) 407-6483
Contact_Electronic_Mail_Address: laurie.morgan@ecy.wa.gov
Hours_of_Service: 0800-1700
Data_Set_Credit: Laurie Morgan, LHG, Dept. of Ecology Water Quality Program
Native_Data_Set_Environment:
Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.2.3552

Data_Quality_Information:
Lineage:
Source_Information:
Type_of_Source_Media: None
Source_Contribution:
Nitrate Priority Areas were developed by Laurie Morgan from various inputs, including USGS risk studies, topography, soils, and geology. The bins are based on inventory of nitrate monitoring results, population, and land use. See Washington Nitrate Prioritization report at https://fortress.wa.gov/ecy/publications/SummaryPages/1610011.html for full documentation.

Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Vector
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains
Point_and_Vector_Object_Count: 57

Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: NAD 1983 HARN StatePlane Washington South FIPS 4602 Feet
Lambert_Conformal_Conic:
Standard_Parallel: 45.83333333333334
Standard_Parallel: 47.33333333333334
Longitude_of_Central_Meridian: -120.5
Latitude_of_Projection_Origin: 45.33333333333334
False_Easting: 1640416.666666667
False_Northing: 0.0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: coordinate pair
Coordinate_Representation:
Abscissa_Resolution: 0.0003280833333333333
Ordinate_Resolution: 0.0003280833333333333
Planar_Distance_Units: foot_us
Geodetic_Model:
Horizontal_Datum_Name: D North American 1983 HARN
Ellipsoid_Name: GRS 1980
Semi-major_Axis: 6378137.0
Denominator_of_Flattening_Ratio: 298.257222101

Entity_and_Attribute_Information:
Detailed_Description:
Entity_Type:
Entity_Type_Label: Nitrate Priority Areas
Entity_Type_Definition: Polygon attribute
Entity_Type_Definition_Source: Ecology
Attribute:
Attribute_Label: County
Attribute_Definition: County Name
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: Name
Attribute_Definition:
Name of Nitrate Priority Area. A Nitrate Priority Area is a recommended area that has been grouped into categories by risk level. These are draft Nitrate Priority Areas for groundwater based on nitrate levels, geology, soils, irrigation, land use, USGS risk maps and topography. We decided what categories these areas belong in using available information in GIS. We based categories on severity of nitrate contamination, population, and agricultural land use. Areas and categories may change based on new information. See the report at for details: https://fortress.wa.gov/ecy/publications/SummaryPages/1610011.html.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: OBJECTID
Attribute_Definition: Internal feature number.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:
Unrepresentable_Domain:
Sequential unique whole numbers that are automatically generated.
Attribute:
Attribute_Label: Shape
Attribute_Definition: Feature geometry.
Attribute_Definition_Source: Esri
Attribute_Domain_Values:
Unrepresentable_Domain: Coordinates defining the features.
Attribute:
Attribute_Label: NpaID
Attribute_Definition: Identification number for the Nitrate Priority Area
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: Bin
Attribute_Definition:
Bin category number. The Nitrate Priority Area Category is based on the number of well locations with high nitrate, population, and land use. Details are in the Nitrate Priority Area Description.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: BinText
Attribute_Definition:
Bin category text. The Nitrate Priority Area Category is based on the number of well locations with high nitrate, population, and land use. Details are in the Nitrate Priority Area Description.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: BinDescription
Attribute_Definition:
Nitrate Priority Area Category Description: We based categories on severity of nitrate contamination, population, and agricultural land use. Areas and categories may change based on new information. See the report at for details: https://fortress.wa.gov/ecy/publications/SummaryPages/1610011.html.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: Population2010
Attribute_Definition:
The population within the Nitrate Priority Area derived from the U.S. 2010 Census
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: PopulationPerSqMi
Attribute_Definition:
The population per square mile within the Nitrate Priority Area as determined from the U.S. 2010 Census
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: TotalDairies
Attribute_Definition: Number of dairies within the Nitrate Priority Area as of 2012
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: TotalCropAcres
Attribute_Definition:
Total crop acres within the Nitrate Priority Area as of 2013 from WSDA crop data
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: FallowAcres
Attribute_Definition:
Total fallow acres within the Nitrate Priority Area as of 2013 from WSDA crop data
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: CRPAcres
Attribute_Definition:
Total Conservation Reserve Program acres within the Nitrate Priority Area as of 2013 from WSDA crop data
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: IrrigatedAcres
Attribute_Definition:
Total irrigated acres within the Nitrate Priority Area as of 2013 from WSDA crop data
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: UnIrrigatedAcres
Attribute_Definition:
Total unirrigated acres within the Nitrate Priority Area as of 2013 from WSDA crop data
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: PCTIrrigated
Attribute_Definition: Percent of NPA that is irrigated as of 2013 from WSDA crop data
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: MaxGE10
Attribute_Definition:
Number of well locations within a Nitrate Priority Area with a maximum nitrate value for the period of record used >= 10 mg/L as N.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: MaxGE5LT10
Attribute_Definition:
Number of well locations within a Nitrate Priority Area with a maximum nitrate value for the period of record used >= 5 mg/L and < 10 mg/L as N.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: MaxGE5
Attribute_Definition:
Number of well locations within a Nitrate Priority Area with a maximum nitrate value for the period of record used >= 5 mg/L as N.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: MaxGE3LT5
Attribute_Definition:
Number of well locations within a Nitrate Priority Area with a maximum nitrate value for the period of record used >= 3 mg/L and < 5 mg/L as N.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: MaxLT3
Attribute_Definition:
Number of well locations within a Nitrate Priority Area with a maximum nitrate value for the period of record used < 3 mg/L as N.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: MaxTotal
Attribute_Definition:
Total number of well locations within a Nitrate Priority Area (one maximum nitrate value per well location)
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: PCTMaxGE10
Attribute_Definition:
Percent of well locations within a Nitrate Priority Area with a maximum nitrate value for the period of record used >= 10 mg/L as N.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: PCTMaxGE5
Attribute_Definition:
Percent of well locations within a Nitrate Priority Area with a maximum nitrate value for the period of record used >= 5 mg/L as N
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: TotalSamples
Attribute_Definition:
Total number of nitrate samples within the Nitrate Priority Area from the data set that includes USGS, Washington Dept. of Ecology and Washington Dept. of Health Drinking Water well data.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: TotalDairyNTonsProduced
Attribute_Definition:
The sum of tons of nitrogen produced by dairies within the Nitrate Priority Area as of 2012. This number does NOT account for losses by volatilization, denitrification, or crop uptake, it is the total produced.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: DairyAcres
Attribute_Definition:
Dairy Total Owned/Rented Acres. More acreage may be available for use than is reported here.
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: Acres
Attribute_Definition: Nitrate Priority Area acres
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: SqMiles
Attribute_Definition: Nitrate Priority Area square miles
Attribute_Definition_Source: Ecology
Attribute:
Attribute_Label: Shape.STArea()
Attribute:
Attribute_Label: Shape.STLength()

Metadata_Reference_Information:
Metadata_Date: 20170508
Metadata_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: Washington State Department of Ecology, Water Quality Program
Contact_Person: Laurie Morgan
Contact_Position: Hydrogeologist
Contact_Address:
Address_Type: mailing
Address: PO Box 47600
City: Olympia
State_or_Province: WA
Postal_Code: 98504-7600
Contact_Voice_Telephone: 360-407-6483
Contact_Electronic_Mail_Address: Laurie.Morgan@ecy.wa.gov
Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time

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