The disposal of manure on agricultural land has caused water quality concerns in many rural watersheds, sometimes requiring state environmental agencies to conduct total maximum daily load (TMDL) assessments of stream nutrients, such as nitrogen (N) and phosphorus (P). A best management practice (BMP) has been developed in response to a TMDL that mandates a 50% reduction of annual P load to the...

In developing TMDL waste-load allocations for the Snake River-Reservoir system in Western Idaho and Eastern Oregon, determinations of the assimilative capacity of the system and the impact of pollutant reduction strategies has been performed using both a statistical-correlation approach and a mechanistic modeling approach. The system included the Lower Snake River, Brownlee Reservoir, Oxbow Res...

Common decision support tools and a growing body of knowledge about ecological recovery can help inform and guide large state and federal restoration programs affecting thousands of impaired waters. Under the federal Clean Water Act (CWA), waters not meeting state Water Quality Standards due to impairment by pollutants are placed on the CWA Section 303(d) list, scheduled for Total Maximum Daily...

Uncertainty is an inevitable source of noise in water quality management and will weaken the adequacy of decisions. Uncertainty is derived from imperfect information, natural variability, and knowledge-based inconsistency. To make better decisions, it is necessary to reduce uncertainty. Conventional uncertainty analyses have focused on quantifying the uncertainty of parameters and variables in ...

The authors gratefully acknowledge the many comments of reviewers from within EPA and stat environmental agencies, as well as the detailed reviews conducted by Lee iii Foreword Although many pollution sources have implemented the required levels of pollution control technology, there are still waters in the nation that do not meet the Clean Water Act goal of " fishable, swimmable. " Section 303...

Definition The US Congress enacted the Clean Water Act in 1972 (P.L. 92-500, the 1972 Amendments to the Federal Water Pollution Control Act), which is the principal law dealing with polluting activity in streams, rivers, lakes, and estuaries of the USA (Copeland, 2006). The Clean Water Act established a water quality standards approach for regulating water quality, with the US Environmental Pro...

The San Joaquin River (SJR) in the Central Valley of California has been designated an impaired waterbody based on its loss of fisheries-related beneficial uses and the river is now subject to regulation under total maximum daily load (TMDL) rules. For impaired waterbodies, numeric standards alone may not be sufficient to establish remediation priorities and priorities must be established by co...