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| Title | Rocky Ford Creek TMDL Study | |||
| Month-Year Published | September 1998 | |||
| Online Availability |
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| Short Description |
Rocky Ford Creek is a Class A surface water currently listed as violating water quality standards numeric criteria for temperature, pH, and dissolved oxygen. It is suspected that criteria violations are due to excessive primary productivity caused by nutrient loading to the creek. The survey data collected for this project support the 303(d) listings for dissolved oxygen and temperature, and suggest that primary productivity and decomposition in Rocky Ford Creek and its adjacent wetlands are the cause for dissolved oxygen criteria violations and also may be the cause of reported pH violations. The temperature violations are due to natural conditions and it is recommended that the creek be delisted for this parameter. (Also see abstract below) | |||
| Publication Number | 98-326 | |||
| Author(s) | Cusimano, B. | |||
| Print Availability | ||||
| Number of pages | 55 pp. | |||
| Keywords | agricultural, creek, dissolved oxygen, fish, fish hatchery, groundwater, lake, nitrogen, nutrient loading, pH, phosphorus, study, temperature, TMDL, Total Maximum Daily Load, water, water quality, wetland | |||
| Subject Waterbodies |
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| Abstract | Long Description |
Rocky Ford Creek is a Class A surface water currently listed as violating water quality standards numeric criteria for temperature, pH, and dissolved oxygen. It is suspected that criteria violations are due to excessive primary productivity caused by nutrient loading to the creek. The survey data collected for this project support the 303(d) listings for dissolved oxygen and temperature, and suggest that primary productivity and decomposition in Rocky Ford Creek and its adjacent wetlands are the cause for dissolved oxygen criteria violations and also may be the cause of reported pH violations. The temperature violations are due to natural conditions and it is recommended that the creek be delisted for this parameter. Historical and survey data collected for this project show that the concentration of nutrients are high in Rocky Ford Creek. The source of the high phosphorus and nitrogen concentrations in the creek is mostly from groundwater feeding Rocky Ford Creek. Agricultural land management practices in upper Crab Creek are the most likely source of the high nutrient concentration in the groundwater. A direct quantitative link between nutrient loading, concentrations in the water column, and dissolved oxygen (or pH) levels in Rocky Ford Creek may not be possible to establish, because of the nature of wetlands and rooted submerged plant processes. However, setting qualitative nutrient loading limits to protect the creek are recommended. In addition, nutrient allocations based on the upcoming Moses Lake nutrient TMDL recommendations may be necessary to ensure that the nutrient contributions from Rocky Ford Creek do not cause an adverse impact on lake water quality. These allocations may require that both groundwater and fish hatchery nutrient contributions be reduced. |
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