USVI Public Records

Document text

Appendix H Report Cards JULY 31, 2016 THIS PAGE INTENTIONALLY LEFT BLANK What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH What is a TMDL? A TMDL (Total Maximum Daily Load) is the allowable amount of a pollutant or other quantifiable parameter (called a “surrogate”) calculated based on the relationship between pollutant sources and instream water quality. Surrogate measures are used for TMDL allocations when the target pollutant does not have a quantifiable loading basis, or is too expensive or difficult to measure. When a waterbody is listed for turbidity, total suspended solids (TSS) concentrations are used as the surrogate pollutant, when listed for dissolved oxygen (DO), BOD is a surrogate and when listed for pH, nutrients (phosphorous and nitrogen) are surrogates. How to interpret load reduction: This load reduction graphic depicts how much reduction (as a percent) is required to comply with the established TMDL. Each assessment unit has one or more target pollutants, which are depicted on the graph in red. Pollutants that are not a significant threat to water quality are depicted in green, although they may also face percent reductions (an added benefit) when target pollutants are reduced. The limiting pollutant determines the placement of the TMDL target line because, once reduced, the TMDL has been met. Surrogate parameters are used to determine the TMDL for some target pollutants. Turbidity and pH are the pollutants of concern The practices that lead to a 34% reduction of sediment will result in a 43 % reduction of phosphorous & nitrogen. The TMDL is met! A reduction in target pollutants also results in reduction of BOD and bacteria. Even though these are not pollutants of concern, they will also be reduced. The greater the percentage, the greater the load reduction Sediment and phosphorous & nitrogen are “surrogate” pollutants for turbidity and pH