Loadings and Impairments
Pollution load reductions required to meet targets and stream impairments to be addressed.
A key objective of watershed planning is to determine the causes of impairment to stream uses and the sources of pollution.
Pollutants, including E. coli, ammonia, nitrogen, phosphorus, dissolved solids, and litter, were identified as exceeding benchmark values and in need of reduction to achieve healthy conditions. Further, impacts to stream habitat were identified due to erosion and degradation of the riparian vegetation zone. Several pollution-generating activities or sources were identified as contributing to the pollution in the Glenns Creek Watershed.
The pollutant load is defined as the amount of mass (e.g., pounds) of a pollutant that flows through a point over a given time period (e.g., day or year). It is calculated by multiplying the concentration of the pollutant by the stream flow rate. The pollutant yield is calculated by dividing the pollutant load by the land area, enabling comparisons between areas of different sizes. Pollutant loads measured at any point reflect contributions from all upstream sources. The amount of load reduction needed can be determined by comparing the existing pollutant load to a target load representing the load if healthy concentrations are maintained.
These pollutant load reduction targets determine the priority areas for management activities. Using literature values and models, these reductions can be allocated to sources in the area to determine the best course of action to achieve load reduction targets through improved management practices.
Urban Sources:
• Sewage
• Pet waste
• Lawn care
• Road salt
• Litter
• Runoff from hardened surfaces
• Mowing and invasive species in streamside vegetation
Rural Sources:
• Manure mismanagement
• Septic failure and lack of maintenance
• Livestock stocking rates, heavy use areas
• Livestock stream access
• Legacy soil and groundwater nutrients
• Stream bank erosion
• Row crop runoff
The interactive map below visualizes pollution loads, yields, and reductions. For erosion and riparian impacts, subwatershed areas are prioritized using an index, and stream impacts are delineated. Click the pollutants to learn more about the types of impacts and where reductions need to occur.
Learn more about the loading and impairment analysis by reading the document below:
Glenns Creek Pollutant Load Allocation and Causes and Source Analysis Report