Copyright (c) 2013 All rights reserved. http://works.bepress.com/andrewhobson Recent documents in Andrew Hobson en-us Sat, 16 Mar 2013 01:48:52 PDT 3600 http://works.bepress.com/andrewhobson/4 http://works.bepress.com/andrewhobson/4 Thu, 14 Mar 2013 09:34:27 PDT A cooperative data collection and modeling effort between the Utah Department of Environmental Quality (Utah DEQ), Division of Water Quality and Utah State University (USU) began in 2010. The primary objectives of this study were to 1) design a data collection approach appropriate to support the population and calibration of QUAL2Kw models for use in a variety of applications; and 2) develop a methodology for populating and calibrating QUAL2Kw given these data. The intended use of the resulting models was to assist in developing numeric nutrient criteria for the state of Utah and provide a starting point for the development of new waste load allocations (WLAs) for 9 water reclamation facilities (WRFs). The objectives were completed by assisting DEQ in collecting the appropriate data in the reaches below WRFs around the state and using these data to populate and calibrate QUAL2Kw models for each of these study sites.

]]> Bethany T. Neilson et al. http://works.bepress.com/andrewhobson/3 http://works.bepress.com/andrewhobson/3 Wed, 12 Sep 2012 09:12:37 PDT Stream water quality and the influence of external loads is commonly understood through the aid of mathematical models that incorporate the influences of biological, chemical, and physical processes. Such models require forcing, population, and calibration/validation data to effectively predict the influences of proposed management strategies. The State of Utah (DWQ) has recently identified QUAL2Kw as the primary water quality model to aid in developing waste load allocation permits as well as assist in determining statewide instream nutrient criteria. In applying this model throughout the state, there were questions regarding the data types and the temporal and spatial frequency necessary to accurately populate the model. This led to the development of a consistent data collection strategy to support model population and calibration. Further, a step-wise procedure was developed for summarizing the data for model population and using different data types to set specific parameters. This was followed by a combined manual and automatic calibration approach. To test these methods, nine field studies were conducted within central and northern Utah streams that receive wastewater effluent. Associated model applications have resulted in defensible predictions and decreased uncertainty in some parameters. However, key issues have been identified within the data collection and modeling approaches that require consideration when interpreting model predictions.

]]> Andrew Hobson et al. Addressing water quality impairments http://works.bepress.com/andrewhobson/2 http://works.bepress.com/andrewhobson/2 Wed, 12 Sep 2012 08:46:05 PDT Stream water quality is increasingly managed with the aid of mathematical or numerical models that incorporate the influences of biological, chemical, and physical processes. Such models require forcing, population, and calibration/validation data to effectively predict the influences of management strategies. Changes to the resolution of these data are anticipated to affect model predictions and, therefore, may bias interpretation of water quality control strategies. By analyzing model sensitivity to these data, information indicating appropriate levels of data resolution can be extracted. In 2010, instream water quality studies were conducted for nine central and northern Utah streams that receive wastewater effluent. Data and preliminary modeling results from a subset of the sites will be presented as well as the key issues identified with the supporting data collection. Information regarding future data collection and modeling efforts necessary to develop appropriate data collection resolution will be discussed. Overall, this effort will aid in guidance to minimize the number of data types and resolution required while maintaining acceptable model uncertainty.

]]> Andrew Joseph Hobson et al. http://works.bepress.com/andrewhobson/1 http://works.bepress.com/andrewhobson/1 Fri, 09 Apr 2010 12:39:33 PDT Limited water resources in Southern Utah with the competing interests of humans and native fishes require careful management. High instream temperatures resulting from low flows are a consideration in managing the Virgin River for two endangered fish species. Throughout these periods, fish behavior changes have been observed during those high turbidity. One hypothesis was that high turbidity decreased the amount of solar radiation in the water column due to increased reflection at the water surface resulting in reduced instream temperatures. To quantify the extent of changes in incoming energy to the river, a water tank was constructed to measure the effects of turbidity on solar radiation reflection off the water surface and attenuation with depth. We found that increases in turbidity led to a linear increase in solar radiation reflection for specific turbidity ranges. We also found that attenuation of solar radiation increased linearly as turbidity increased for specific turbidity ranges. The effects of turbidity on solar radiation behavior were translated into changes in instream temperatures through the use of an instream temperature model. The results indicated during summer low flow conditions that turbidity increases from 30-500 NTU decreased instream temperatures 1 degree Celcius on average with maximum increases of 2 degrees Celcius.

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