Water Rights Analysis Package Modeling System
Llano River with fisherman. ©2018 Ray Uherek.


water availability

How to Cite

Wurbs, Ralph A. 2021. “Water Rights Analysis Package Modeling System”. Texas Water Journal 12 (1). College Station, Texas:68-90. https://doi.org/10.21423/twj.v12i1.7108.


The water rights analysis package simulates surface water development, allocation, management, and use and performs reliability and frequency analyses of simulation results. The computer modeling system facilitates assessments of hydrologic and institutional water availability and reliability in satisfying requirements for reservoir storage, water supply diversions, environmental instream flows, and hydroelectric energy generation. Reservoir system operations for flood control can be simulated. Capabilities are also provided for tracking salinity concentrations. Basin-wide impacts of water resources development projects and management practices are modeled. The modeling system is generalized for application anywhere, with input datasets being developed for particular river systems of concern. The water availability modeling system maintained by the Texas Commission on Environmental Quality and routinely applied by the professional water management community consists of the water rights analysis package and simulation input datasets for all of the river basins of Texas. Model-users modify the input datasets as appropriate to evaluate alternative water use scenarios, development projects, and management strategies of interest. This paper explores concepts and methodologies incorporated in the water rights analysis package and other comparable modeling systems, implementation of water availability modeling in Texas, and contributions to effective water management.


Alexander K, Henderson R. 2020. Chapter 12 Determining surface water availability. In: Sahs MK, editor. Essentials of Texas water resources. 6th Edition. Austin (Texas): State Bar of Texas. Available from: https://www.texasbarpractice.com/product/essentials-of-texas-water-resources/.

Asquith WH, Bumbarger JR. 2014. Linkage of the soil and water assessment tool and Texas water availability model to simulate the effects of brush management on monthly storage of Canyon Lake, South-Central Texas. Reston (Virginia): U.S. Geological Survey. 42 p. Scientific Investigations Report 2013-5239. Available from: https://pubs.usgs.gov/sir/2013/5239/.

Bista A. 2015. River/reservoir system water availability modeling support for drought management. Master of Science Thesis. College Station (Texas): Texas A&M University. Available from: https://oaktrust.library.tamu.edu/handle/1969.1/155724.

CDM Smith, Inc. 2016. Evaluation and documentation of the state of Texas water availability model and water rights analysis package. Fort Worth (Texas): U.S. Army Corps of Engineers Fort Worth District. 195 p.

Chen J, Chan SN. 2007. Water resources sustainability in the East River in South China using Water Rights Analysis Package. In: Oxley L, Kulasiri D, editors, MODSIM 2007, International Congress on Modelling and Simulation. Modeling and Simulation Society of Australia and New Zealand. 1985–1991. Available from: https://www.mssanz.org.au/MODSIM07/papers/34_s36/WaterResources_s36_Chen_.pdf.

Demirel M, Wurbs RA. 2017. Assessment of flood control capabilities for alternative reservoir storage allocations. Turkish Journal of Water Science & Management, Republic of Turkey Ministry of Forestry and Water Affairs. 6777(1):108-136. Available from: https://doi.org/10.31807/tjwsm.297150.

[HEC] Hydrologic Engineering Center. 1998. HEC-5 simulation of flood control and conservation systems, user's manual. Version 8. Davis (California): U.S. Army Corps of Engineers. CPD5A. Available from: https://www.hec.usace.army.mil/publications/ComputerProgramDocumentation/HEC-5_UsersManual_(CPD-5).pdf

[HEC] Hydrologic Engineering Center. 2009. HEC-DSSVue HEC data storage system visual utility engine, user’s manual. Version 2.1. Davis (California): U.S. Army Corps of Engineers. CPD-79. Available from: https://www.hec.usace.army.mil/software/hec-dssvue/.

[HEC] Hydrologic Engineering Center 2013. HEC-ResSim reservoir system simulation, user's manual. Version 3.1. Davis (California): U.S. Army Corps of Engineers. CPD-82. Available from: https://www.hec.usace.army.mil/software/hec-ressim/.

[HEC] Hydrologic Engineering Center. 2019. HEC-SSP statistical software package, user’s manual. Version 2.2. Davis (California): U.S. Army Corps of Engineers. CPD-86. Available from: https://www.hec.usace.army.mil/software/hec-ssp/.

Hoffpauir, RJ. 2010. Daily time step simulation with a priority order based surface water allocation model. Ph.D. Dissertation. College Station (Texas): Texas A&M University. Available from: https://oaktrust.library.tamu.edu/handle/1969.1/ETD-TAMU-2010-12-8703.

Johns ND, Hess M, Kaderka S, McCormick L, McMahon J. 2004. Bays in peril: a forecast for freshwater flows to Texas estuaries. Austin (Texas): Gulf Coast Natural Resource Center, National Wildlife Federation. 54 p. Available from: https://texaslivingwaters.org/deeper-dive/bays-in-peril-a-forecast-for-freshwater-flows-to-texas-estuaries/.

Kim TJ, Kim JH. 2016. Evaluation of the impact of priority order water rights on single reservoir operation. Journal of Korean Society of Hazard Mitigation. 16(1):221-226. Available from: https://doi.org/10.9798/KOSHAM.2016.16.1.221.

Koch H, Grunewald U. 2009. A comparison of modeling systems for the development and revision of water resources management plans. Water Resources Management. 23(7):1403-1422. Available from: https://doi.org/10.1007/s11269-008-9333-x.

Labadie JW. 2004. Optimal operation of multireservoir systems: state-of-art review. Journal of Water Resources Planning and Management. 130(2):93-111. Available from: https://doi.org/10.1061/(ASCE)0733-9496(2004)130:2(93) .

Labadie JW, Larson R. 2007. MODSIM 8.1: river basin management decision support system, user manual and documentation. Fort Collins (Colorado): Colorado State University. Available from: http://modsim.engr.colostate.edu/.

Maass A, Hufschmidt MM, Dorfman R, Thomas HA, Marglin SA, Fair GM. 1966. Design of water resource systems. Cambridge (Massachusetts): Harvard University Press.

Martin QW. 1983. Optimal operation of multiple reservoir systems. Journal of Water Resources Planning and Management. 109(1):58-74. Available from: https://doi.org/10.1061/(ASCE)0733-9496(1983)109:1(58).

Martin QW. 1987. Optimal daily operations of surface-water systems. Journal of Water Resources Planning and Management. 113(4):453-470. Available from: https://doi.org/10.1061/(ASCE)0733-9496(1987)113:4(453) .

McPherson M. 2019. HEC CWMS team visits Texas water management offices. Advances in Hydrologic Engineering. Davis (California): USACE Hydrologic Engineering Center. Available from: https://www.hec.usace.army.mil/newsletters/HEC_Newsletter_Winter2019.pdf.

Muttiah RS, Wurbs RA. 2005. Chapter 6 Climate change effects on the water supply in some major river basins. In: Lal R, Uphoff N, Stewart BA, Hansen DO, editors. Climate change and global food security. London (United Kingdom): Taylor & Francis/CRC Press. Available from: https://www.taylorfrancis.com/books/edit/10.1201/9781420028614/climate-change-global-food-security-rattan-lal-norman-uphoff-stewart-david-hansen.

Nature Conservancy. 2009. Indicators of Hydrologic Alteration (IHA) Software Version 7.1 User’s Manual. Available from: https://www.conservationgateway.org/ConservationPractices/Freshwater/EnvironmentalFlows/MethodsandTools/IndicatorsofHydrologicAlteration/Documents/IHAV7.pdf.

Opdyke DR, Oborny EL, Vaugh SK, Mayes KB. 2014. Texas environmental flow standards and the hydrology-based environmental flow regime methodology. Hydrological Sciences Journal. 59(3-4):820-830. Available from: https://doi.org/10.1080/02626667.2014.892600 .

Pauls MA, Wurbs RA. 2016. Environmental flow attainment metrics for water allocation modeling. Journal of Water Resources Planning and Management. 142(8):04016018. Available from: https://doi.org/10.1061/(ASCE)WR.1943-5452.0000652.

Ryu M. 2015. Developing homogenous sequences of river flows and performing comparative analyses of flow characteristics. Ph.D. Dissertation. College Station (Texas): Texas A&M University. Available from: https://oaktrust.library.tamu.edu/handle/1969.1/156367.

[TWDB] Texas Water Development Board. 1974. Analytical techniques for planning complex water resource systems. Austin (Texas). Report 183. Available from: https://www.twdb.texas.gov/publications/reports/numbered_reports/doc/R183/report183.asp.

[TWDB] Texas Water Development Board. 2017. Water for Texas 2017. Austin (Texas). Available from: https://www.twdb.texas.gov/waterplanning/swp/2017/index.asp.

Wurbs RA. 1993. Reservoir system simulation and optimization models. Journal of Water Resources Planning and Management. 119(4):455-472. Available from: https://doi.org/10.1061/(ASCE)0733-9496(1993)119:4(455).

Wurbs RA. 1995. Water rights in Texas. Journal of Water Resources Planning and Management. 121(6):447-454. Available from: https://doi.org/10.1061/(ASCE)0733-9496(1995)121:6(447).

Wurbs RA. 1996. Modeling and analysis of reservoir system operations. Upper Saddle River (New Jersey): Prentice Hall Division of Pearson Publishing. 356 p.

Wurbs RA. 2005a. Comparative evaluation of generalized river/reservoir system models. College Station (Texas): Texas Water Resources Institute. 203 p. TR-282. Available from:


Wurbs RA. 2005b. Texas water availability modeling system. Journal of Water Resources Planning and Management. 131(4):270-279. Available from: https://doi.org/10.1061/(ASCE)0733-9496(2005)131:4(270).

Wurbs RA. 2006. Methods for developing naturalized monthly flows at gaged and ungaged sites. Journal of Hydrologic Engineering. 11(1):55-64. Available from: https://doi.org/10.1061/(ASCE)1084-0699(2006)11:1(55).

Wurbs RA. 2009. Salinity simulation with WRAP. College Station (Texas): Texas Water Resources Institute. 89 p. TR-317. Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2020/12/SalinityManual.pdf.

Wurbs RA. 2012. Reservoir/river system management models. Texas Water Journal. 3(1):26-41. Available from: https://doi.org/10.21423/twj.v3i1.1066.

Wurbs RA. 2015. Sustainable statewide water resources management in Texas. Journal of Water Resources Planning and Management. 141(12):A4014002-1-10. Available from: https://doi.org/10.1061/(ASCE)WR.1943-5452.0000499.

Wurbs RA. 2019a. Fundamentals of water availability modeling with WRAP. 9th Edition. College Station (Texas): Texas Water Resources Institute. 114 p. TR-283. Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2021/02/FundamentalsManual.pdf.

Wurbs RA. 2019b. Water rights analysis package (WRAP) river system hydrology. 3rd Edition. College Station (Texas): Texas Water Resources Institute. 241 p. TR-431. Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2021/02/HydrologyManual.pdf.

Wurbs RA. 2019c. Daily water availability model for the Brazos River Basin and San Jacinto-Brazos Coastal Basin. College Station (Texas): Texas Water Resources Institute. 238 p. TR-513. Available from: https://twri.tamu.edu/publications/technical-reports/2019-technical-reports/tr-513/.

Wurbs RA. 2019d. Daily water availability model for the Trinity River Basin, Texas Commission on Environmental Quality, Contract 582-18-80410. 193 p. Austin (Texas). Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2020/12/TrinityDailyWAM.pdf.

Wurbs RA. 2020a. Daily water availability model for the Neches River Basin, Texas Commission on Environmental Quality, Contract 582-18-80410. 199 p. Austin (Texas). Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2020/12/DailyNechesWAM.pdf.

Wurbs RA. 2020b. Institutional framework for modeling water availability and allocation. Water. Special Issue of Featured Papers on Water Resources Management, Policy, and Governance. 12(10):2767. Available from: https://doi.org/10.3390/w12102767.

Wurbs RA. 2021a. Water rights analysis package (WRAP) modeling system reference manual. 13th Edition. College Station (Texas): Texas Water Resources Institute. 464 p. TR-255. Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2021/02/ReferenceManual.pdf.

Wurbs RA. 2021b. Water rights analysis package (WRAP) modeling system users manual. 13th Edition. College Station (Texas): Texas Water Resources Institute. 273 p. TR-256. Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2021/02/UsersManual.pdf.

Wurbs RA. 2021c. Storage and regulation of river flows by dams and reservoirs. Texas Water Journal. 12(1):129-149. Available from: https://doi.org/10.21423/twj.v12i1.7106.

Wurbs RA, Ayala RA. 2014. Reservoir evaporation in Texas. Journal of Hydrology. 510(2014):1-9. Available from: https://doi.org/10.1016/j.jhydrol.2013.12.011.

Wurbs RA, Bergman CE, Carriere PE, Walls WB. 1988. Hydrologic and institutional water availability in the Brazos River Basin. College Station (Texas): Texas Water Resources Institute. 246 p. TR-144. Available from: https://oaktrust.library.tamu.edu/handle/1969.1/6187.

Wurbs RA, Hoffpauir RJ. 2013. Environmental flows in water availability modeling. College Station (Texas): Texas Water Resources Institute. 285 p. TR-440. Available from: https://oaktrust.library.tamu.edu/handle/1969.1/149195.

Wurbs RA, Hoffpauir RJ. 2016. Environmental flow requirements in a water availability modeling system. Sustainability of Water Quality and Ecology. 9-10(2017):9-21. Available from: https://doi.org/10.1016/j.swaqe.2016.05.003.

Wurbs RA, Hoffpauir RJ. 2021. Water rights analysis package (WRAP) daily modeling system. 4th Edition. College Station (Texas): Texas Water Resources Institute. 346 p. TR-430. Available from: http://42moiy3v9hvn2311gt2qdhpu-wpengine.netdna-ssl.com/wp-content/uploads/sites/84/2021/02/DailyManual.pdf.

Wurbs RA, Lee CH. 2009. Salinity budget and WRAP salinity simulation studies for the Brazos river/reservoir system. College Station (Texas): Texas Water Resources Institute. 324 p. TR-352. Available from: https://oaktrust.library.tamu.edu/handle/1969.1/90516.

Wurbs RA, Lee CH. 2011. Salinity in water availability modeling. Journal of Hydrology. 409(1-2):451-459. Available from: https://doi.org/10.1016/j.jhydrol.2011.08.042.

Wurbs RA, Muttiah RS, Felden F. 2005. Incorporation of climate change in water availability modeling. Journal of Hydrologic Engineering. 10(5):375-385. Available from: https://doi.org/10.1061/(ASCE)1084-0699(2005)10:5(375).

Wurbs RA, Sanchez-Torres G, Dunn DD. 1994. Reservoir/river system reliability considering water rights and water quality. College Station (Texas): Texas Water Resources Institute. 201 p. TR-165. Available from: https://oaktrust.library.tamu.edu/handle/1969.1/6165.

Wurbs RA, Sanchez-Torres G. 1996. Simulation of a surface water allocation system. Water International. 21(1):46-54. Available from: https://doi.org/10.1080/02508069608686490.

Wurbs RA, Schnier ST, Olmos HE. 2012. Short-term reservoir storage frequency relationships. Journal of Water Resources Planning and Management. 138(6):597-605. Available from: https://doi.org/10.1061/(ASCE)WR.1943-5452.0000218.

Wurbs RA, Walls WB. 1989. Water rights modeling and analysis. Journal of Water Resources Planning and Management. ASCE. 115(4):416-430. Available from: https://doi.org/10.1061/(ASCE)0733-9496(1989)115:4(416).

Wurbs RA, Zhang Y. 2014. River system hydrology in Texas. College Station (Texas): Texas Water Resources Institute. 237 p. TR-461. Available from: https://twri.tamu.edu/publications/technical-reports/2014-technical-reports/tr-461/.

Yerramreddy AR, Wurbs RA. 1996. Water resources allocation based on network flow programming. Civil Engineering and Environmental Systems. 13(1):75-87. Available from: https://doi.org/10.1080/02630259608970187.

Zagona EA, Fulp TJ, Shane R, Magee T, Goranflo HM. 2001. Riverware: a generalized tool for complex reservoir system modeling. Journal of the American Water Resources Association. 37(4):913-929. Available from: https://doi.org/10.1111/j.1752-1688.2001.tb05522.x.

Zhang R, Chen J, Cui G. 2010. Drought and water supply reliability of East River (Dongjiang) Basin in South China. In: Zhang C, Tang H. Advances in Water Resources and Hydraulic Engineering: Proceedings of 16th Congress of the International Association for Hydro-Environmental Research. Springer Publishers. 298-307. Available from: https://doi.org/10.1007/978-3-540-89465-0_54.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Copyright (c) 2021 Ralph A. Wurbs