Diagnostic Systems Approach to Watershed Management

Davisson, M L

Lawrence Livermore National Laboratory

关键词: Surface Waters;    Management;    Sterilization;    Chlorination;    Missouri River;   

DOI  :  10.2172/15005708
RP-ID  :  UCRL-ID-142554
RP-ID  :  W-7405-ENG-48
RP-ID  :  15005708

美国|英语

来源: UNT Digital Library

【 摘 要 】

The water quality of discharge from the surface water system is ultimately dictated by land use and climate within the watershed. Water quality has vastly improved from point source reduction measures, yet, non-point source pollutants continue to rise. 30 to 40% of rivers still do not meet water quality standards for reasons that include impact from urban storm water runoff, agricultural and livestock runoff, and loss of wetlands. Regulating non-point source pollutants proves to be difficult since specific dischargers are difficult to identify. However, parameters such as dissolved organic carbon (DOC) limit the amounts of chlorination due to simultaneous disinfection by-product formation. The concept of watershed management has gained much ground over the years as a means to resolve non-point source problems. Under this management scheme stakeholders in a watershed collectively agree to the nature and extent of non-point sources, determine water quality causes using sound scientific approaches, and together develop and implement a corrective plan. However, the ''science'' of watershed management currently has several shortcomings according to a recent National Research Council report. The scientific component of watershed management depends on acquiring knowledge that links water quality sources with geographic regions. However, there is an observational gap in this knowledge. In particular, almost all the water quality data that exists at a utility are of high frequency collected at a single point over a long period of time. Water quality data for utility purposes are rarely collected over an entire watershed. The potential is high, however, for various utilities in a single watershed to share and integrate water quality data, but no regulatory incentives exist at this point. The only other available water quality data originate from special scientific studies. Unfortunately these data rarely have long-term records and are usually tailored to address unrelated research questions. The goal of this research was to investigate whether scientific research tools were available that could provide evidence that links water quality and land type. In particular, could such tools be used on raw water at the treatment point rather than monitoring over a large geographic spanning a watershed. This report summarizes the utility of using isotopic tracers to better understand sources of non-point source pollution and their relation to industry standard water quality measurements. In this study we have found that much of the water quality data generated by utilities is under-interpreted in the context of understanding watershed processes. For example, the City of St. Louis depends solely on the Missouri River for drinking water, but due to large variability in discharge and runoff sources, they are faced with DOC concentrations that vary nearly a factor of three within a single season. The relationship between discharge and concentration has not been constrained. However, we found a linear correlation between the DOC concentration and the fractional amount of downstream discharge (derived from within the State of Missouri). This correlation relates directly to differences in land use and climate between the upstream and downstream portions of the river basin.