Browsing by Subject "TMDL"
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Item A water quality assessment of the import of turfgrass sod grown with composted dairy manure into a suburban watershed(Texas A&M University, 2005-02-17) Richards, Chad EdwardConcentrated animal feeding operations (CAFOs) have caused water quality concerns in many rural watersheds, sometimes forcing the State of Texas to conduct Total Maximum Daily Load (TMDL) assessments of stream nutrients such as nitrogen (N) and phosphorus (P). One suggested Best Management Practice (BMP) is the export of phosphorus (P) through turfgrass sod produced with composted dairy manure from an impaired rural watershed to an urban watershed. The manure-grown sod releases P slowly and would not require additional P fertilizer for up to 20 years in the receiving watershed. This would eliminate P application to the sod and improve the water quality of urban streams. The Soil and Water Assessment Tool (SWAT) was used to model a typical suburban watershed that would receive the transplanted sod. The objective of the modeling was to determine the water quality changes due to the import of sod transplanted from turf fields and grown with composted dairy manure. The SWAT model was calibrated to simulate historical flow and sediment and nutrient loading to Mary's Creek. The total P stream loading to Mary's Creek was lower when manure-grown sod was imported instead of commercial sod grown with inorganic fertilizers. Yet, flow, sediment yield, and total N yield increased equally for both cases at the watershed outlet. The SWAT simulations indicate that a turfgrass BMP can be used effectively to import manure P into an urban watershed and reduce in-stream P levels when compared to sod grown with inorganic fertilizers.Item Bacterial total maximum daily load (TMDL): development and evaluation of a new classification scheme for impaired waterbodies of Texas(Texas A&M University, 2005-02-17) Paul, SabuUnder the Clean Water Act (CWA) program the Texas Commission on Environmental Quality (TCEQ) listed 110 stream segments with pathogenic bacteria impairment in 2000. The current study was conducted to characterize the watersheds associated with the impaired waterbodies. The main characteristics considered for the classification of waterbodies were designated use of the waterbody, land use distribution, density of stream network, average distance of a land of a particular use to the closest stream, household population, density of on-site sewage facilities (OSSF), bacterial loading due to the presence of different types of farm animals and wildlife, and average climatic conditions. The availability of observed in-stream fecal coliform bacteria concentration data was evaluated to obtain subgroups of data-rich and data-poor watersheds within a group. The climatic data and observed in-stream fecal coliform bacteria concentrations were analyzed to find out seasonal variability of the water quality. The watershed characteristics were analyzed using the multivariate statistical analysis techniques such as factor analysis/principal component analysis, cluster analysis, and discriminant analysis. Six groups of watersheds were formed as result of the statistical analysis. The main factors that differentiate the clusters were found to be bacterial contribution from farm animals and wildlife, density of OSSF, density of households connected to public sewers, and the land use distribution. Two watersheds were selected each from two groups of watersheds. Hydrological Simulation Program-FORTRAN (HSPF) model was calibrated for one watershed within each group and tested for the other watershed in the same group to study the similarity in the parameter sets due to the similarity in watershed characteristics. The study showed that the watersheds within a given cluster formed during the multivariate statistical analysis showed similar watershed characteristics and yielded similar model results for similar model input parameters. The effect of parameter uncertainty on the in-stream bacterial concentration predictions by HSPF was evaluated for the watershed of Salado Creek, in Bexar County. The parameters that control the HSPF model hydrology contributed the most variance in the in-stream fecal coliform bacterial concentrations corresponding to a simulation period between 1 January 1995 and 31 December 2000.Item Field-scale evaluation of a system for manure export through turfgrass sod(Texas A&M University, 2006-10-30) Choi, In HoA total maximum daily load (TMDL) assessment in the Upper North Bosque River (UNBR) has mandated reductions of soluble reactive phosphorus (SRP). The large concentrations of dairies in the UNBR watershed have been identified as a source of the SRP. Agricultural best management practices (BMPs) can be used to reduce in-stream loads of manure nutrients from confined dairy feeding operations (CAFOs). A new BMP utilizes turfgrass sod to export composted dairy manure nutrients out of the impaired watershed in a sustainable manner. Previous plot-scale experiments have showed that 46 to 77% of applied phosphorus (P) and 36 to 47% of applied nitrogen (N) were removed in a single sod harvest. Two, 1.4 ha turfgrass fields were instrumented to measure runoff flow and sediment and nutrient transport. One turfgrass field was topdressed with composted dairy manure and fertilizer N and the other with fertilizer N only. A total of 3.5% of the applied manure P and 3.1% of applied manure N were lost in the surface runoff over a 1.5 year period. The runoff data from the experimental fields were used to calibrate and validate Soil and Water Assessment Tool (SWAT) model simulations of flow, sediment, organic, and mineral nutrients. The Nash-Sutcliffe model fit statistic was greater than 0.6 for flow, sediment, and nutrients during the calibration period and greater than 0.3 during the validation period. Research results indicated that turfgrass sod can be used to export composted dairy manure out of impaired watersheds to improve water and soil quality.Item From chaos to harmony : public participation and environmental policy(2011-12) Dulay, Marcel; Eaton, David J.; Rodriguez, Victoria E.; Spelman, William G.; Browning, Larry D.; Maxwell, Madeline M.Water quality issues in the Leon River watershed in Texas exemplify the challenges water resource managers and the public face in the ongoing effort to improve water quality in our nation’s water bodies. Some pollutant sources are difficult to regulate and likely managed through non-regulatory means, such as voluntary action. The Leon River challenge is how to go beyond regulations to address the concerns of citizens and produce options they want to develop and implement voluntarily that address a common good. This dissertation argues that voluntary measures work only if those who must take action support the action, otherwise conflict can occur. Thus, it is critical to learn what people are willing to do to promote the public good (e.g., swimmable streams). This can be achieved through an effective public process. Public participation processes may have barriers that impede success, such as inadequate access, intimidation, competing interests, limited accountability, and scientific mistrust. This dissertation developed process enhancements to overcome these barriers based on documented public participation principles. This research tested whether specific enhancements can improve the quality of a public process and achieve desired process outcomes. This dissertation reports on quasi-experiments with stakeholders making actual environmental decisions. The findings suggest that these enhancements are capable of reducing conflict and reducing the time to produce environmental policy. Five process enhancements (representation, film, narratives, deliberative decision-making, and decision support) were put into operation to provide options for government agencies and stakeholders to consider when undertaking public participation processes. The lack of access can be avoided by giving stakeholders voice with representation through different types of meetings levels (e.g., focus groups and town hall meetings). Films, when captured, edited, and shown to others, can remove the mechanisms typically associated with the intimidation perceived by speakers during discussions. Narratives were used to collect information about stakeholders to develop a deeper understanding of the diversity of interests affected by a policy, avoiding gridlock from positional bargaining. Deliberative decision-making (no voting) can assure stakeholders have real and equitable decision-making power, with scenarios collaboratively developed that address the common good. Application of a decision support system (DSS) as an overlay to a scientific model can provide stakeholders direct access to science so they can develop scenarios, evaluate alternatives, and choose solutions.Item Growth Kinetics of Wildlife E. coli Isolates in Soil and Water(2012-07-16) Gallagher, MeghanBacteria are the major cause of surface water contamination in the United States. US Environmental Protection Agency (USEPA) uses the Total Maximum Daily Load (TMDL) process to regulate the E. coli loads from fecal sources in a watershed. Different point and non-point sources can contribute to the fecal contamination of a waterbody including municipal and on-site wastewater treatment plants, livestock, birds, and wildlife. Unfortunately, wildlife sources in many rural watersheds are poorly characterized. E. coli is also known to persist in waterbodies when no known fecal sources are present. In this study, E. coli from wildlife fecal material was enumerated. It was found that E. coli concentrations varied with the season the fecal samples were collected. When studying the fate of E. coli under different environmental factors, no growth was observed in soil at 4% moisture content and in water at 10 degrees C. The highest E. coli growth was recorded in water at 30 degrees C. It can be seen from these results that there was variation in the fate of E. coli under different environmental conditions. The fate of E. coli in the environment is a complex process and is influenced by many factors and their interactions, making it difficult to predict. The findings from this study along with additional studies can be used to improve the accuracy of model predictions to estimate the E. coli loads in watersheds.Item Locating turfgrass production sites for removal of phosphorus in Erath County, Texas(Texas A&M University, 2004-09-30) Hanzlik, Jeremy EdwardThe North Bosque River watershed of central Texas hosts a large portion of diary production in the state. In recent years, the Texas Commission on Environmental Quality (TCEQ), formerly known as the Texas Natural Resource Conservation Commission (TNRCC), has applied a Total Maximum Daily Load Program for soluble phosphorus to the watershed. Best management practices (BMPs) are now necessary to remedy the issue of excess phosphorus. This thesis explores the application of GIS as an agricultural planning tool in support of a BMP for the region. The suggested BMP calls for the production of turfgrass sod using composted dairy manure; this sod is then transported at a profit from the watershed and provides an economically sustainable means to reduce the nutrient loading in the watershed. Using GIS, a geospatial database was developed with available data from government and institutional sources. As part of the development process, these sites were verified by field technicians and the results were combined in the GIS to refine the database. This database demonstrates the suitability of GIS as a tool for large-scale planning in agriculture.Item Occurrence and Fate of Escherichia Coli from Non-Point Sources in Cedar Creek Watershed, Texas(2011-08-08) Padia, ReemaFecal contamination is the pollution caused by the microorganisms residing in the intestine of warm blooded animals and humans. Bacteria are the prime cause of contamination of surface waters in the US. The transport of microorganisms into waterways can have detrimental effects on water quality and human health especially if the pathogenic strains are ingested. E. coli is used as an indicator of fecal contamination. Detection of these bacteria in a water body above set limits poses a potential health hazard. Various sources contribute to the bacterial contamination of a water body. The sources need to be identified and quantified for their E. coli content to measure bacteria loads in the waterbody accurately. In many cases, in-situ re-growth is also believed to be a considerable source of E. coli. Also re-growth of E. coli in landscapes due to favorable environmental conditions (e.g., rainfall after dry weather conditions) is one of the major phenomena affecting E. coli concentration in streams. Thus the environmental factors like temperature and soil moisture that influence transport, persistence, re-growth, and survival of E. coli in landscapes were studied. The objective of this study was to identify, characterize and quantify E. coli loads from feces of four different animals and monitor survival, growth and re-growth at four different temperatures and moisture contents over a period of seven days. Findings of this research will aid in Watershed Protection Plan (WPP) development and Total Maximum Daily Load (TMDL) development to address impairment from point and non-point source pollution of E. coli. Wildlife and range cattle manure samples responsible for fecal contamination of Cedar Creek were identified and four fecal sources out of those were quantified for the E. coli concentrations. No significant difference was found upon comparing the E. coli concentration for each species between the genders. Sub-adult cattle demonstrated significantly higher E. coli concentrations than adult cattle. Growth and die-off rates were measured at different temperatures (0degreesC, 10degreesC, 25degreesC, and 50degreesC) and moisture conditions (1%, 25% 56.5% and 83%). E. coli concentrations in cattle and raccoons feces showed highest survivability and growth at 20degreesC out of all the temperatures studied. There was no survival of E. coli from either species at 50degreesC after 24 h. E. coli in cattle and raccoons samples exhibited greater growth at lower, nearly aerobic soil moisture content (25%) for all days compared to nearly anaerobic soil moisture content (83%).Item Spatially explicit load enrichment calculation tool and cluster analysis for identification of E. coli sources in Plum Creek Watershed, Texas(2009-06-02) Teague, Aarin ElizabethAccording to the 2004 303(d) List, 192 segments are impaired by bacteria in the State of Texas. Impairment of streams due to bacteria is of major concern in several urban watersheds in Texas. In order to assess, monitor and manage water quality, it is necessary to characterize the sources of pathogens within the watershed. The objective of this study was to develop a spatially explicit method that allocates E.coli loads in the Plum Creek watershed in East Central Texas. A section of Plum Creek is classified as impaired due to bacteria. The watershed contains primarily agricultural activity and is in the midst of an urban housing boom. Based on a stakeholder input, possible sources E. coli were first identified in the different regions of the watershed. Locations of contributing non-point and point sources in the watershed were defined using Geographic Information Systems (GIS). By distributing livestock, wildlife, wastewater treatment plants, septic systems, and pet sources, the bacterial load in the watershed was spatially characterized. Contributions from each source were then quantified by applying source specific bacterial production rates. The rank of each contributing source was then assessed for the entire watershed. Cluster and discriminant analysis was then used to identify similar regions within the watershed for assistance in selection of appropriate best management practices. The results of the cluster analysis and the spatially explicit method were compared to identify regions that require further refinement of the SELECT method and data inputs.