The Issue:
Puget Sound watershed nutrient loads are known to have an impact on marine water quality along with wastewater treatment plants discharging to Puget Sound. To effectively reduce and control nutrient loads to the Sound, the Washington State Department of Ecology needs a regional watershed model that fits within their Puget Sound Nutrient Source Reduction Project’s management framework that provides predictions of nutrient loads in the streams and rivers throughout the Puget Sound.
How USGS will Help:
In collaboration with the Washington State Department of Ecology, the US Geological Survey will compile all relevant water quality monitoring data and watershed attributes throughout the Puget Sound and attempt to create a statistically significant SPARROW (SPAtially Referenced Regression On Watershed attributes) model capable of predicting seasonal nutrient loads to the Puget Sound. The model will be designed to help identify stream and river segments with the greatest loads as well as to identify the factors most likely responsible for the elevated levels of nutrients.
Problem
Puget Sound watershed nutrient loads are known to have an impact on marine water quality along with wastewater treatment plants discharging to Puget Sound. In order to effectively reduce and control nutrient loads to the Sound, the Washington State Department of Ecology needs a regional watershed model that fits within their Puget Sound Nutrient Source Reduction Project’s management framework. The proposed model is the US Geological Survey’s SPARROW (SPAtially Referenced Regression On Watershed attributes) model. SPARROW is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as nutrient sources and environmental factors that affect rates of delivery of nutrients to streams and in-stream processing. It is designed to utilize existing nutrient monitoring data and watershed information to explain the factors that affect water quality, examine the statistical significance of contaminant sources, environmental factors, and transport processes in explaining predicted nutrient loads, and provide a statistical basis for estimating stream nutrient loads in unmonitored locations.
Objectives
The USGS is proposing to develop a SPARROW model to estimate mean annual and seasonal total phosphorus (TP) and total nitrogen (TN) loads to the Puget Sound from the contributing watershed, and to estimate the relative annual and seasonal contribution from various sources of TP and TN from each modeled stream reach throughout the watershed.
Specific objectives for the mean annual and seasonal SPARROW model for Puget Sound are:
- Characterize mean annual and seasonal TP and TN loads from specific stream reaches throughout the Puget Sound watershed.
- Identify significant anthropogenic and natural sources contributing TP and TN throughout the watershed.
- Identify the proportion of seasonal and annual TP and TN loads originating from wastewater treatment plants compared to non-point sources.
- Publish the Puget Sound model in a USGS report and provide training to Ecology staff on its operation.
Relevance and Benefits
The proposed study directly meets the needs of Ecology’s need to have a regional watershed model that fits within their Puget Sound Nutrient Source Reduction Project’s (PSNSRP) management framework. Outputs from the SPARROW model will provide them the information necessary to characterize loads of TP and TN entering the Puget Sound in addition to helping them identify specific sources and areas with elevated levels of nutrients on a mean annual and seasonal basis. Such information will play a critical role in their nutrient source reduction efforts. In addition to the benefits to Ecology, the proposed work also addresses many of the goals and objectives outlined by the USGS in the Strategic directions for U.S. Geological Survey water science.
Approach
SPARROW is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as nutrient sources and environmental factors that affect rates of delivery of nutrients to streams and in-stream processing. Calibration data are derived from water-quality monitoring information at sites located throughout a study area. Those data are associated with reaches in a digital stream network to define spatial relations among the monitoring sites and among their drainage areas. Detailed geospatial data bases are then linked with the stream network drainage areas to define the basin characteristics in all of the areas that drain to monitoring locations and to all individual stream reaches. Once the linkages are developed, all of these types of data are combined in one data base that is used for model development. The core of the model consists of a nonlinear regression equation describing the non-conservative transport of contaminants from point and non-point sources on land to rivers and through the stream and river network.
SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
The Issue:
Puget Sound watershed nutrient loads are known to have an impact on marine water quality along with wastewater treatment plants discharging to Puget Sound. To effectively reduce and control nutrient loads to the Sound, the Washington State Department of Ecology needs a regional watershed model that fits within their Puget Sound Nutrient Source Reduction Project’s management framework that provides predictions of nutrient loads in the streams and rivers throughout the Puget Sound.
How USGS will Help:
In collaboration with the Washington State Department of Ecology, the US Geological Survey will compile all relevant water quality monitoring data and watershed attributes throughout the Puget Sound and attempt to create a statistically significant SPARROW (SPAtially Referenced Regression On Watershed attributes) model capable of predicting seasonal nutrient loads to the Puget Sound. The model will be designed to help identify stream and river segments with the greatest loads as well as to identify the factors most likely responsible for the elevated levels of nutrients.
Problem
Puget Sound watershed nutrient loads are known to have an impact on marine water quality along with wastewater treatment plants discharging to Puget Sound. In order to effectively reduce and control nutrient loads to the Sound, the Washington State Department of Ecology needs a regional watershed model that fits within their Puget Sound Nutrient Source Reduction Project’s management framework. The proposed model is the US Geological Survey’s SPARROW (SPAtially Referenced Regression On Watershed attributes) model. SPARROW is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as nutrient sources and environmental factors that affect rates of delivery of nutrients to streams and in-stream processing. It is designed to utilize existing nutrient monitoring data and watershed information to explain the factors that affect water quality, examine the statistical significance of contaminant sources, environmental factors, and transport processes in explaining predicted nutrient loads, and provide a statistical basis for estimating stream nutrient loads in unmonitored locations.
Objectives
The USGS is proposing to develop a SPARROW model to estimate mean annual and seasonal total phosphorus (TP) and total nitrogen (TN) loads to the Puget Sound from the contributing watershed, and to estimate the relative annual and seasonal contribution from various sources of TP and TN from each modeled stream reach throughout the watershed.
Specific objectives for the mean annual and seasonal SPARROW model for Puget Sound are:
- Characterize mean annual and seasonal TP and TN loads from specific stream reaches throughout the Puget Sound watershed.
- Identify significant anthropogenic and natural sources contributing TP and TN throughout the watershed.
- Identify the proportion of seasonal and annual TP and TN loads originating from wastewater treatment plants compared to non-point sources.
- Publish the Puget Sound model in a USGS report and provide training to Ecology staff on its operation.
Relevance and Benefits
The proposed study directly meets the needs of Ecology’s need to have a regional watershed model that fits within their Puget Sound Nutrient Source Reduction Project’s (PSNSRP) management framework. Outputs from the SPARROW model will provide them the information necessary to characterize loads of TP and TN entering the Puget Sound in addition to helping them identify specific sources and areas with elevated levels of nutrients on a mean annual and seasonal basis. Such information will play a critical role in their nutrient source reduction efforts. In addition to the benefits to Ecology, the proposed work also addresses many of the goals and objectives outlined by the USGS in the Strategic directions for U.S. Geological Survey water science.
Approach
SPARROW is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as nutrient sources and environmental factors that affect rates of delivery of nutrients to streams and in-stream processing. Calibration data are derived from water-quality monitoring information at sites located throughout a study area. Those data are associated with reaches in a digital stream network to define spatial relations among the monitoring sites and among their drainage areas. Detailed geospatial data bases are then linked with the stream network drainage areas to define the basin characteristics in all of the areas that drain to monitoring locations and to all individual stream reaches. Once the linkages are developed, all of these types of data are combined in one data base that is used for model development. The core of the model consists of a nonlinear regression equation describing the non-conservative transport of contaminants from point and non-point sources on land to rivers and through the stream and river network.