Conservation Matters January 2012

The Texas Land, Water and Wildlife Connection

New Publications/Papers and Training Courses

Methodologies for Analyzing Impact of Urbanization on Irrigation Districts, G. Bonaiti, G. Fipps, Texas Water Resources Institute, TR-419

The region of Texas along the Mexican border has been experiencing rapid urban growth. This has caused fragmentation of many irrigation districts who are struggling to address the resulting challenges. In this paper, we analyze the growth of urban area and its impact on water distribution networks in three Texas border counties over the ten year period, 1996 to 2006. In particular, we discuss alternative procedures to assess such impacts, and we evaluate their effectiveness in identifying critical areas.

Evaluation of the CRITERIA Irrigation Scheme Soil Water Balance Model in Texas, G. Bonaiti, G. Fipps, Texas Water Resources Institute, TR-418

The CRITERIA model was created in the 1990s in Italy, and is based on the soil water balance computation procedures developed at the Wageningen University in the Netherlands in the 1980s. CRITERIA has been used as an analysis and regional water planning tool (e.g seasonal crop yield and water use predictions, impact of climate change scenarios), and is currently used in Northern Italy to update the regional water balance on a weekly base. The model can handle a multilayered soils and computes daily average values related to the soil water balance (actual evaporation and transpiration, water flow between layers, deep percolation, surface runoff, and subsurface runoff). Automatic algorithms allow for calculation and scaling of data which may not be available such as detailed meteorological data and soil-water properties. Outputs can be readily used in a Geographic Information System (GIS). The required inputs are precipitation, air temperature, soil texture, and crop management data (planting and harvesting dates, irrigation method and applied volumes). The model allows for input of additional data such as actual ET, soil conductivity, and soil-water characteristics. If this data is not available, the model can estimate them. The model requires calibration using a combination of measured soil moisture and actual ET.

A Progress Report for the Arroyo Colorado Watershed Protection Plan, T.A. Berthold and J. Flores, Texas Water Resources Institute, TR-413

The Arroyo Colorado (AC) is located in the Lower Rio Grande Valley of South Texas and flows through the middle of Hidalgo and Cameron counties. The lower 16 miles of the AC form the boundary between Cameron and Willacy counties. The AC drainage area is a sub-watershed of the Nueces-Rio Grande Coastal Basin, also known as the Lower Laguna Madre Watershed.

Arroyo Colorado Watershed Protection Plan Implementation Project Final Report, T.A. Berthold, J. Flores, Texas Water Resources Institute, TR-411

The Arroyo Colorado (AC) is an ancient channel of the Rio Grande that extends eastward for about 90 miles from near the city of Mission, Texas through southern Hidalgo County to the city of Harlingen in Cameron County, eventually discharging into the Laguna Madre near the Cameron-Willacy County line. Since 1996, the AC has been impaired for low dissolved oxygen (DO) levels within the tidal segment; not meeting the aquatic life use designated by the State of Texas and described in the Water Quality Standards. In addition, bacteria has always been a parameter of concern and as of 2006, the AC became impaired due to elevated levels.

The Pond Destroyers: Common and Giant Salvinia, L. Gregory, M. Masser, Texas Water Resources Institute, EM 109

Salvinias are non-native, floating aquatic ferns. There are two species of salvinia in Texas, common salvinia (Salvinia minima) and giant salvinia (Salvinia molesta). While giant salvinia has been called the worst or most invasive aquatic plant in the world, common salvinia is also very invasive and problematic. Both salvinias can double in size within a week or less with good summer growing conditions. The salvinias are native to South America and were imported into the United States by the water garden and aquarium industries. Common salvinia was first noted in Texas in 1992 and giant salvinia in 1998. Since then the salvinias have covered tens of thousands of acres of public and private waters in Texas.

Estimating the distribution and abundance of the black-capped vireo in Texas, T. M. McFarland, H. A. Mathewson, M. L. Morrison, R. T. Snelgrove, J. E. Groce, K. Skow, B. A. Collier, R. N. Wilkins, Texas A&M Institute of Renewable Natural Resources, RR-1

We present here the largest and most comprehensive study of the black-capped vireo (Vireo atricapilla) in Texas using an appropriate study design. The goals of our research were to (1) gather data to determine the distribution of black-capped vireos throughout their range in Texas, (2) evaluate topographic, climatic, and vegetative factors driving the distribution of vireos, (3) determine how vireos distribute themselves locally and whether they are clustering on the landscape, (4) determine what habitat characteristics describe local population abundance, (5) use those data to develop a distribution model that estimates probability of vireo occurrence based on landscape and vegetative characteristics and (6) validate this distribution model using an independent dataset. From this research, we have developed a decision-support tool that allows a user to quickly determine the occupancy probability of an area based on several user-defined metrics, providing a user-friendly interface to our predictive occupancy models.

TWRI and IRNR Training Courses

Conservation Science Social Media Feb. 13
2012 Bacterial Source Tracking - State of the Science Conference Feb. 28–29
Introduction to ArcGIS 10 March 27–28
SWAT for Beginners April 9–10
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