2015 Technical Reports

Authors: G.D. Di Giovanni, E.A. Casarez, J. A. Truesdale,T.J. Gentry, P. Wanjugi, E. Martin, K. Wagner

Significant progress was made in expanding and refining the Texas E. coli BST Library and updating the template-Standard Operating Procedures. In particular, additional known source isolates were added to address underrepresented wildlife species. Temporal stability evaluations using Leon River known source isolates collected over a 10-year period of time revealed that approximately half of the E. coli strains from known sources may change over time even within the same watershed. Similarly, temporal evaluation of E. coli water isolates from the Leon River watershed revealed similar temporal variability. Thus, it was not surprising that a fairly high amount of geographical variability was also found for known source isolates. However, source-specific isolates were also identified that have broader geographical distribution and temporal stability, which deserve further attention moving forward with library refinement.

Authors: K. Rafi. K.L. Wagner, T.J. Gentry, R. Karthikeyan

This project examined the relationship of E. coli concentrations and recreational use to both stream order and watershed size. To determine possible ecoregion effects, the E. coli data used in this study were obtained from monitoring stations located on freshwater streams located in three ecoregions in Texas and Oklahoma – the Central Great Plains, Central Oklahoma/Texas Plains and South Central Plains (Ecoregions 27, 29, and 35, respectively).

Authors: L. Gregory, R. Karthikeyan, T. Gentry, D. Harmel, K. Wagner, R. Lopez

Bacteria water quality impairments are the most common water quality issue in Texas and are a considerable source of impairments nationally. Fecal indicator bacteria such as Escherichia coli (E. coli) and enterococci derived from birds and mammals are used as a measure of a waterbody’s ability to support contact recreation. Relationships between monitored levels of E. coli and enterococcus have been established with human contraction of a gastrointestinal illness from pathogenic organisms and serve as the basis for water quality standards that protect contact recreation. Stakeholder processes are often undertaken to improve the quality of impaired waters, define pollutant sources, and develop strategies to reduce bacteria loading to streams. Questions are often asked during these processes regarding the fate and transport of these bacteria in various environmental settings, the distribution of E. coli sources across watersheds, and how they respond to changes in water quality. Past research conducted has worked to address these questions; however, additional work is warranted.

Re-created stream mesocosms were used to develop an improved understanding of E. coli fate and transport in the environment under controlled treatment conditions. Nutrient amendments that mimic increases in nutrient concentrations seen from nonpoint source pollutant loadings and wastewater effluent loadings were applied to determine if E. coli concentrations would change as a result of the amendments and alter growth or decay relative to a control mesocosm. No E. coli growth response was observed in any trial, and no significant differences in decay rates were observed either. This suggests that a single nutrient addition to a stream environment is not sufficient to produce a growth response in the ambient E. coli community.

Soil and runoff samples collected from three controlled land uses were processed to enumerate E. coli and allow individual colonies to be isolated and fingerprinted for bacteria source tracking (BST). E. coli source contributions to native prairie, managed hay pasture, and cultivated cropland sites were determined using 7-way source identification splits. In all cases, wildlife were found to be the primary E. coli contributor. Unexpectedly, cattle and humans were identified as sources of E. coli in runoff and soils from some of the sites. Cattle are not actively stocked nor have they been stocked at any of these sites for at least three years, and no known sources of human fecal deposition have occurred in these watersheds. This demonstrates the complex diversity of E. coli in unimpacted environments and the potential for bacteria to be translocated by transmission vectors.

Authors: P. Harrington, R. D. Lacewell, C. R. Taylor

The world population is growing rapidly, and the amount of arable land is decreasing. This raises the issue of how to feed the 2050 projected population of nine billion people. Another issue is the presence of “food deserts.” Food deserts are defined as urban neighborhoods and rural towns without ready access to fresh, healthy, and affordable food.

The purpose of this report is to examine possible alternatives for food production that are also located in close proximity to demand. Included in non-traditional production agriculture are several concepts currently in use, including greenhouses (covered agriculture), backyard gardens (called Victory Gardens during WW II), agriculture-designated land within urban areas, underground facilities (bomb shelters), urban agriculture in housing developments, and converted warehouses. Other production concepts are presented to demonstrate the breadth of discussion regarding meeting future food demand.

In the several cases of unique, non-traditional agriculture, each is a new industry with few players in the market, suggesting time will be the final decision-maker on viability (agronomic and economic). Greenhouses have been a part of production agriculture for centuries, with the technology well-defined. But retrofitting abandoned warehouses or constructing high rise facilities, as well as production in high rise housing units, will take time to perfect the systems involved, including a water and reuse system, fertilization, pest and disease control, harvesting, overall quality control, and logistics.

The necessary components of non-traditional food production facilities are resources, land, water, equipment and finances. Highly fertile land has for the most part been allocated to crop cultivation, and the quantity of high-quality water for irrigation is declining. Non-traditional systems typically have a much smaller land footprint and are highly efficient in water use. The implication is that non-traditional food production systems will provide society with more quantity, plus improved quality, of high-value food products per unit of land and per unit of water.

This is a broad, brief review of actual production facilities, as well as projections for the future. Included are greenhouses, retrofitted warehouses, below-surface facilities, high rise facilities, and production near cities. This piece is intended to provide insight into the broad range of non-traditional food production facilities emerging and envisioned at this time. The mention of any business is not to be interpreted as endorsement or suggestion that it is viable.

Authors: B. Jonescu, L. Gregory, A. Berthold, K. Wagner

This project was initiated to provide updated water quality data for Arenosa Creek in order to determine the persistence of the bacterial impairment of the watershed, while also informing decision makers on potential remedial actions. Indicator bacteria, such as E. coli, are indigenous to the intestinal tracts and therefore feces of birds and warmblooded animals.They are not normally harmful to human health, but can indicate the presence of pathogens that can cause disease.Typical sources of these bacteria in watersheds include birds and mammals (humans, livestock, wildlife, etc.) that are either directly deposited into a water body or enter diffusely through surface runoff.

This study was designed to understand overall trends in bacterial levels, along with determining if levels observed exceed the applied water quality standard. After completion of monitoring, data will be used by decision makers to help formulate management measures in order to address the water quality impairment.

Authors: P. Harrington, R. Lacewell

The Texas Lower Rio Grande Valley is a large agricultural region with limited water resources. With rapid expansion in population and industrial growth, there is an increasing competition for water, particularly in times of drought or due to under deliveries of water by Mexico. This competition is further aggravated by expected global climate change and outlook for reduced rainfall and higher temperatures. To address the issue of limited water supply, a major initiative is to accelerate conservation by cities, irrigation districts, and industry and on farms. Progress has been significant for cities and irrigation districts but less so on farms.

After years of court cases and state decisions, the majority of Rio Grande surface water rights in the region are held by irrigation districts. Therefore, there is little incentive for farmers to make investments in equipment or management to conserve water since any savings reverts to the irrigation districts. This paper is a review of the evolution of irrigation in South Texas, the process for establishing water rights and the implications for on-farm water conservation. A set of on-farm water conservation alternatives is presented with insight on water savings and economic implications followed by potential strategies to provide incentives to farmers to implement water conservation on-farm and how the region as a whole benefits.

Authors: N. Dictson, A. Berthold, C. Entwistle, H. Simpson, S. Lewey

The State of Texas has more than 191,000 miles of rivers and streams that comprise corridors of great economic, social, cultural, and environmental value. Riparian degradation is a major threat to water quality, in-stream habitat, terrestrial wildlife, aquatic species, and overall stream health. The Texas Riparian and Stream Ecosystem Education Program is funded by the U.S. Environmental Protection Agency (EPA) through the Texas State Soil and Water Conservation Board. The Texas Water Resources Institute coordinated and partnered with the Texas A&M AgriLife Extension Service, Texas A&M AgriLife Research, Texas State Soil and Water Conservation Board (TSSWB), EPA, Texas Parks and Wildlife Department, USDA Natural Resource Conservation Service, Texas A&M Forest Service, TTU Llano River Field Station, TCEQ, and Texas State University-River Systems Institute to conduct the Texas Riparian and Stream Ecosystem training project. The project supports the Texas Nonpoint Source Management Program’s goal of protecting and restoring water quality. It provides training to land owners, land managers, water and natural resource professionals, and the general public in impaired watersheds through the help of local partners.

Authors: T.A. Berthold, T. Gentry

Public and private wells that use alluvial aquifers as a drinking water source have an increased risk of contamination from pathogens. This reconnaissance study, conducted by the Texas Water Resources Institute (TWRI) and subcontractors, focused on Segment 1428 of the Colorado River as a site of highest contamination risk based on (1) density of OSSFs, (2) groundwater chemistry, and (3) areas Texas Commission on Environmental Quality (TCEQ) Water Supply Division has previously identified as either having fecal coliform positive samples in raw well samples or when 1 micron filtration samples are indicative of “Groundwater under the influence of Surface Water.”

 Groundwater (and adjacent surface water) sampling was conducted following dam releases from Tom Miller Dam and transmitted through Longhorn Dam. Water chemistry data (pH, specific conductance, dissolved oxygen, temperature) was evaluated to determine the effects of the mixing of surface water and groundwater. A transect of wells at different distances from the river was sampled to determine to what degree distance from the river controls the level of pathogens. Transects were sampled at one location along the river. Water samples were analyzed for bacteria. Polymerase chain reaction (PCR) for Cryptosporidium and for selected viruses was conducted on selected samples (minimum of 3). This final report provides an account of activities conducted under this scope of work as well as work from a companion Clean Water Act (CWA) 604(b) grant project titled “Pathogen Risk to Human Health in Potable Water Related to Nonpoint Sources of Contamination: Colorado River Alluvium Case Study, River Segment 1428.” 

Authors: R. D. Lacewell, P, Harrington

There is much ado about the potential for applications of UAVs to take precision agriculture to the next level. The economic value of UAVs to agriculture has been broadly touted with little basis for the estimates. This paper is an attempt to provide background to the potential value of UAVs improving crop and livestock production. Unfortunately, there is not a simple method to estimate this value.

A first consideration of using UAVs is where UAV technology can assist in making decisions about irrigation, use of nutrients, insect and disease control, and similar issues. The area in which the UAVs cannot provide valuable information and impact decisions by producers relates to weather-related losses such as hail, wind, blowing dust, cold, excessive moisture, drought, and such. Therefore, the objective of this paper is to identify losses and expenses where a UAV with appropriate sensors could have a positive impact of reducing losses in yield and quality. Several sources of information are used to develop estimates for Texas and then for the U.S. This effort is based on crops due to lack of availability of livestock information.

Authors: L. Gregory, A. Gitter, K. Lazar

The 2012 Texas Integrated Report – Texas 303(d) List identifies 11 impaired waterbody segments along the Navasota River due to Escherichia coli (E.coli) bacteria (Figure 1). The Clean Water Act (CWA) requires water bodies that are impaired for a specific parameter or condition, to be restored and their water quality maintained. Efforts to restore impaired waterbodies include additional monitoring, assessing the current standards and conditions of the waterbody, stakeholder outreach and education, and exploring opportunities for developing watershed restoration plans. Previous reports regarding the watershed have revealed E. coli levels to be elevated in specific tributaries since as early as 1999 (TCEQ 2013b; BRA 2011). The river’s elevated E.coli levels do not comply with the state’s recreational water quality criteria for primary contact recreation, which is established at 126 cfu/100 mL. Segment 1210A of the river, which lies above Lake Mexia, is an unclassified waterbody that has been named impaired by bacterial contamination since 2002. The Navasota River below Lake Mexia, segment 1253, is considered impaired for depressed dissolved oxygen (DO) because of frequent low water levels (BRA 2011). The project’s goals include: (1) characterize the current bacteria loading and sources for the watershed, (2) determine the necessary levels of loading reduction to restore the water body, (3) work with stakeholders to select and prioritize management measures necessary to restore the waterbody, and (4) develop a watershed protection plan for the Navasota River below Lake Limestone.

This report discusses the climatic, physical, demographic, and hydrological conditions as well the potential sources of pollution within the watershed. The report also includes an assessment of current and historical conditions within the Navasota River watershed and aims to begin the process of defining its current bacteria levels. Information is largely presented on a watershed-wide basis; however, where appropriate and possible, information is discussed on a more refined scale.

Authors: D. Rajsekhar, V. P. Singh

Natural disasters like droughts have a huge socio-economic impact on society. Despite being an important component of mitigation, the concept of vulnerability in association with extreme events has not been explored much. This report presents a systematic approach for the assessment of drought hazard and identification of drought vulnerability indicators pertinent to the state of Texas. A novel drought index known as Multivariate Drought Index (MDI) was used to simultaneously quantify multiple physical forms of drought. A composite risk assessment was then carried out by considering both hazard and vulnerability components. The risk, hazard, and vulnerability components were quantified using standardized indices like Drought Hazard Index (DHI), Drought Vulnerability Index (DVI), and Drought Risk Index (DRI). A suitable classification scheme was adopted for these indices to group regions into classes ranging from low to high. Mapping of DHI, DVI, and DRI classes led to the generation of risk, hazard and vulnerability maps for Texas. The report emphasizes the importance of including vulnerability of the study area in the event of drought while drafting planning measures. Ultimately, the study aims at bridging the gaps existing in the current drought research, which even though substantial, still fails to address some of the issues, and for developing a comprehensive framework for better understanding of droughts in Texas which will help decision makers to formulate a more effective adaptation and mitigation strategy in future.

Authors: L.R. Dutton, M.E. Rister, R.D. Lacewell, A.W. Sturdivant

With increasing population and global economic growth, the pressure on natural resources becomes more intense. Water is a prime example of increasing demand among many users, including environmental priorities. A typical approach for increasing water availability is to look to conservation and/or alternative technological developments for water supply. These strategies involve issues with investment, recurring costs, and a temporal evaluation. Capital budgeting methodology of discounting future streams of costs and benefits to estimate a present value is well established. Applying capital budgeting techniques to water management strategies is an effective method to account for and compare alternative annual water saving levels and expected useful lives. This methodology includes ‘normalizing’ such flows by calculating the respective alternative projects’ net present values and associated annuity equivalents using a discount rate. The issue of “appropriate discount” rate is not the point of this paper, but rather, if dollars are discounted, what are the perspectives on discounting future water savings to a present value. The issue does not lend itself to a consensus, but rather, provides interesting implications, particularly when prioritizing alternative projects. Presented herein are attitudes across resource specialists with arguments related to what to include in a discount rate, private sector versus public sector, and the impact of also discounting physical units such as water on the priority of alternative projects. A case study of three alternative water conservation projects and how the ranking is impacted by alternative assumptions in financial and physical water discounting is presented.