Salinity is a major determinant of where and how water resources are used worldwide. Natural salt pollution severely constrains the beneficial use of large amounts of water in Texas and neighboring states. High salinity loads in several major river/reservoir systems, including the Brazos River, originate largely from salt seeps and springs in isolated areas of the upper river basins located in the Permian Basin geologic region. Research objectives were (1) to improve salinity simulation capabilities of the Water Rights Analysis Package (WRAP) modeling system, and (2) to develop a better understanding of the occurrence, transport, and impacts of salinity in the Brazos River and Lakes Possum Kingdom, Granbury, and Whitney. Water volume budgets and total dissolved solids load budgets were developed for five river reaches covering 405 miles of the upper Brazos River. Methodologies were developed for creating and applying WRAP salinity input datasets. The WRAP modeling system was expanded and applied to the entire Brazos River Basin to investigate alternative modeling premises and impacts of salinity and salinity control measures on water supply capabilities. Water and salinity budget analyses of the Brazos River system based primarily on measured stream flow, reservoir storage, and total dissolved solids data compiled by the U.S. Geological Survey were performed to explore the characteristics of flow and storage volumes and salinity loads and concentrations in the river/reservoir system. WRAP salinity input datasets were developed based on results from the salinity budget study. One dataset was designed and applied specifically for testing salinity routing methods and calibrating salinity routing parameters. A second complete basin salinity dataset was developed and applied to simulate the Brazos River Basin for alternative management strategies. The results of the simulations demonstrate, for example, that previously proposed salt control impoundments can significantly reduce salinity loads and concentrations in the three reservoirs and at all locations on the Brazos River from the impoundments downstream to the Gulf of Mexico. The WRAP salinity simulation features are designed to provide flexibility in combining water quantity simulation datasets from the Texas Water Availability Modeling System or other sources, which may be very complex, with available salinity data which varies in extent and format between different river basins. The modeling capabilities demonstrated by the Brazos River Basin study can be applied in other river basins as well.

This open access book is an outcome of the collaboration between the Soil and Water Management & Crop Nutrition Section, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency (IAEA), Vienna, Austria, and Dr. Shabbir A Shahid, Senior Salinity Management Expert, Freelancer based in United Arab Emirates.The objective of this book is to develop protocols for salinity and sodicity assessment and develop mitigation and adaptation measures to use saline and sodic soils sustainably. The focus is on important issues related to salinity and sodicity and to describe these in an easy and user friendly way. The information has been compiled from the latest published literature and from the authors’ publications specific to the subject matter. The book consists of six chapters. Chapter 1 introduces the terms salinity and sodicity and describes various salinity classification systems commonly used around the world. Chapter 2 reviews global distribution of salinization and socioeconomic aspects related to salinity and crop production. Chapters 3 covers comprehensively salinity and sodicity adaptation and mitigation options including physical, chemical, hydrological and biological methods. Chapter 4 discusses the efforts that have been made to demonstrate the development of soil salinity zones under different irrigation systems. Chapter 5 discusses the quality of irrigation water, boron toxicity and relative tolerance to boron, the effects of chlorides on crops. Chapter 6 introduces the role of nuclear techniques in saline agriculture.