Browsing by Subject "best management practices"
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Item Assessing the Effectiveness of Water Quality Best Management Practices for Grazing-Lands(2013-12-10) Clary, Calvin RussellBest management practices (BMPs) aim to reduce bacterial loading caused by grazing cattle. Relatively little is known about the effectiveness of alternative shade, alternative water, rip-rap, and prescribed grazing as potential BMPs. Prescribed grazing evaluated how stocking rate affected bacterial loading. E. coli concentrations in runoff samples were compared between plots with various stocking rates. GPS collars were used to determine how a shade pavilion, water source, or rip-rap effected cattle distribution within a stream and riparian pasture by comparing time cattle spent at a location before and after implementing the BMPs. While plots were stocked or within 14 days of being destocked, E. coli concentrations were significantly higher than destocked pastures. No significant differences were observed between E. coli concentrations in runoff from heavily stocked, moderately stocked, or non-grazed pastures when pastures had been destocked for greater than 14 days. On average, the shade structure reduced cattle's dependence on riparian shade by 30%. The alternative water BMP did not reduce the amount of time cattle spent within the riparian zone; however, the study was limited to one trial. Riparian rip-rap trials were inconclusive; however, preliminary rip-rap trials showed 20 to 40 cm diameter rip-rap was effective at modifying cattle trough preference. Advances in microbial source tracking, specifically Bacteroides, have allowed better identification of bacterial sources. However, genetic variability within some Bacteroides sequences may undermine the accuracy of these molecular markers. Localized gene-copy curves were created from 12 bovine fecal samples from a single herd, and qPCR assays were used to determine if they better correlated Bacteroides and E. coli populations. Sequences were pyro-sequenced to see if mismatches occurred within primer/probe regions. Base-pair mismatches occurred, and affected qPCR efficiencies. Fecal pollution load estimations were overestimated by using sequences with more mismatches. Genetic diversity was observed within samples from all locations, and indicated genetic variability within Bacteroides populations occurs within a single location as much as between locations. Thus, creating standard curves for individual watersheds would not necessarily improve pollution load estimations.Item Development of a mult-objective strategic management approach to improve decisions for pavement management practices in local agencies(2009-05-15) Chang Albitres, Carlos MartinMultiple objectives are often used by agencies trying to manage pavement networks. Often alternative investment strategies can accomplish the agencies? target objectives. If the goal is to achieve the target objectives at the minimum cost, an approach is needed to assist agencies in identifying investment strategies capable of meeting the targets while minimizing costs. The approach used by the agency should not be limited to an analytical method to mathematically solve the funding allocation problem. Finding mechanisms to ensure the sustainability and efficiency of the investment strategy over time is a great challenge that needs to be addressed by the approach. The challenge is even greater for local agencies where resources are usually limited. This research develops a multi-objective strategic management approach oriented to improving decisions for pavement management practices in local agencies. In this approach, target objectives are tied to key pavement network parameters in the management process. A methodology to identify the best combination of projects to meet target objectives at the minimum cost while maximizing treatment effectiveness is provided as a result of the research. Concepts from the pavement management program (PMP) of the Metropolitan Transportation Commission (MTC) of the San Francisco Bay Area were used as a basis for developing the methodology. Four pavement network parameters are considered for setting the target objectives over the agency?s planning horizon: the average network pavement condition index (PCI), average network remaining life, percent of the pavement network in good condition, and percent of the pavement network in poor and very poor condition. Results from a case study show that funding allocation methods influence the allocation of preservation and rehabilitation funds among pavement network groups, affecting budget estimates and future condition of the pavement network. It is also concluded that the use of mechanisms that facilitate data integration and the flow of knowledge across management levels can contribute to making better informed decisions. Hence, the adoption of the multi-objective strategic pavement management approach developed in this dissertation should lead to identifying more efficient investment strategies for achieving the pavement network state desired by a local agency at a minimum cost.