Managed Aquifer Recharge as a Tool to Enhance Sustainable Groundwater Management in California

A growing population and an increased demand for water resources have resulted in a global trend of groundwater depletion. Arid and semi-arid climates are particularly susceptible, often relying on groundwater to support large population centers or irrigated agriculture in the absence of sufficient surface water resources. In an effort to increase the security of groundwater resources, managed aquifer recharge (MAR) programs have been developed and implemented globally. MAR is the approach of intentionally harvesting and infiltrating water to recharge depleted aquifer storage. California is a prime example of this growing problem, with three cities that have over a million residents and an agricultural industry that was valued at 47 billion dollars in 2015. The present-day groundwater overdraft of over 100 km3 (since 1962) indicates a clear disparity between surface water supply and water demand within the state. In the face of groundwater overdraft and the anticipated effects of climate change, many new MAR projects are being constructed or investigated throughout California, adding to those that have existed for decades. Some common MAR types utilized in California include injection wells, infiltration basins (also known as spreading basins, percolation basins, or recharge basins), and low-impact development. An emerging MAR type that is actively being investigated is the winter flooding of agricultural fields using existing irrigation infrastructure and excess surface water resources, known as agricultural MAR. California therefore provides an excellent case study to look at the historical use and performance of MAR, ongoing and emerging challenges, novel MAR applications, and the potential for expansion of MAR. Effective MAR projects are an essential tool for increasing groundwater security, both in California and on a global scale. This chapter aims to provide an overview of the most common MAR types and applications within the State of California and neighboring semi-arid regions

Regional and global hydrology and water resources issues: The role of international and national programs

This paper presents an overview of water resources issues in the context of world population growth, climate change, and variability, and provides examples of how these issues affect local and regional water policy concerns. Also discussed is the associated research of the international scientific community in regard to physically-based modeling of the hydrological cycle, with special focus on the Global Energy and Water cycle EXperiment (GEWEX) Programme. The critical role of precipitation measurements for climate model accuracy is emphasized, with a review of several satellite methods and strategies for improving precipitation measurements. Finally, the impact of semiarid regions on global hydrologic issues is underscored with a review of research conducted by SAHRA, the National Science Foundation Science and Technology Center dedicated to Sustainability of semi-Add Hydrology and Riparian Areas

Quantifying future water resources availability and agricultural productivity in agro-urban river basins

Includes bibliographical references.2022 Fall.Climate change can have an adverse effect on agricultural productivity and water availability in semi-arid regions, as decreases in surface water availability can lead to groundwater depletion and resultant losses in crop yield due to reduced water for irrigation. Competition between urban and agricultural areas intensifies groundwater exploitation as surface water rights are sold to growing municipalities. These inter-relationships necessitate an integrated management approach for surface water, groundwater, and crop yield as a holistic system. This dissertation provides a novel integrated hydrologic modeling approach to quantify future water resources and agricultural productivity in agro-urban river basins, particularly in arid and semi-arid regions where surface water and groundwater are managed conjunctively to sustain urban areas and food production capacity. This is accomplished by i) developing an integrated hydrologic modeling code that accounts for groundwater and surface water processes and exchanges in large regional-scale managed river basins, and demonstrating its use and performance in the economically diverse South Platte River Basin (SPRB), a 72,000 km2 river basin located primarily in the state of Colorado, USA; ii) using the model to understand possible future impacts imposed by climate variation on water resources (surface water and groundwater) and agricultural productivity; and iii) quantifying the combination impacts of agriculture-to-urban water trading and climate change on groundwater resources within the basin. This dissertation presents an updated version of SWAT-MODFLOW that allows application to large agro-urban river basins in semi-arid regions. SWAT provides land surface hydrologic and crop yield modeling, whereas MODFLOW provides subsurface hydrologic modeling. Specific code changes include linkage between MODFLOW pumping cells and SWAT HRUs for groundwater irrigation and joint groundwater and surface water irrigation routines. This conjunctive use, basin-scale long-term water resources, and crop yield modeling tool can be used to assess future water and agricultural management for large river basins across the world. The updated modeling code is applied to the South Platte River Basin, with model results tested against streamflow, groundwater head, and crop yield throughout the basin. To assess the climate change impacts on water resources and agricultural productivity, the coupled SWAT-MODFLOW modeling code is forced with five different CMIP5 climate models downscaled by Multivariate Adaptive Constructed Analogs (MACA), each for two climate scenarios, RCP4.5, and RCP8.5, for 1980-2100. In all climate models and emission scenarios, an increase of 3 to 5 °C in annual average temperature is projected by the end of the 21st century, whereas variation in projected precipitation depends on topography and distance from the mountains. Based on the results of this study, the worst-case climate model in the basin is IPSL-CM5A-MR-8.5. Under this climate scenario, for a 1 °C increase in temperature and the 1.3% reduction in annual precipitation, the basin will experience an 8.5% decrease in stream discharge, 2-5% decline in groundwater storage, and 11% reduction in crop yield. In recent decades, there has been a growing realization that developing additional water supplies to address new demands is not feasible. Instead, managing existing water supplies through reallocations is necessary to tackle water scarcity and climate change. However, third-party effects associated to water transfers has limited the growing water market. This study also quantifies the combination impacts of agriculture-to-urban water trading (widely known as 'buy and dry') and climate change on groundwater availability in semi-arid river basins through the end of 21st century, as groundwater pumping increases to satisfy irrigation water lost to the urban sector. For this analysis, we use the hydrological modeling tool SWAT-MODFLOW, forced by projected water trading amounts and two downscaled GCM climate models, each for two emission scenarios, RCP4.5 and 8.5. According to the results of this study, agriculture-to-urban water trading imposes an additional basin-wide 2% reduction in groundwater storage, as compared to changes due to climate. However, groundwater storage changes for local subbasins can be up to 8% and 10% through the mid-century and end of the century, respectively

GEO - SOLUTION TECHNIQUES FOR GROUNDWATER EXPLORATION

Groundwater has been one of the major purest sources of water in the world. This is because the source is been stored in an aquifer beneath the earth’s surface. However, exploring this source require certain skills or techniques in order to ease the trauma experienced by the searcher. Over the years various geophysical techniques have been applied to explore this source but with little or no success due to the approach. In this research therefore, aeromagnetic and electrical resistivity techniques were integrated to explore this source in Dahomey basin, southwestern Nigeria. The result established that no single geophysical technique can be used for detailed geophysical studies of an area. But the combination of these geophysical techniques yields better result because they complement each other

Groundwater research and management: integrating science into management decisions. Proceedings of IWMI-ITP-NIH International Workshop on "Creating Synergy Between Groundwater Research and Management in South and Southeast Asia," Roorkee, India, 8-9 February 2005

Groundwater management / Governance / Groundwater development / Artificial recharge / Water quality / Aquifers / Groundwater irrigation / Water balance / Simulation models / Watershed management / Water harvesting / Decision making / South East Asia / Bangladesh / China / India / Nepal / Pakistan / Syria

Integrated Water Resources Management Karlsruhe 2010 : IWRM, International Conference, 24 - 25 November 2010 conference proceedings

In dieser Arbeit werden dual-orthogonal, linear polarisierte Antennen für die UWB-Technik konzipiert. Das Prinzip zur Realisierung der Strahler wird vorgestellt, theoretisch und simulativ untersucht, sowie messtechnisch verifiziert. Danach werden Konzepte zur Miniaturisierung der Strahler dargelegt, die anschließend zum Aufbau von Antennengruppen verwendet werden. Die Vorteile der entwickelten Antennen werden praktisch anhand des bildgebenden Radars und des Monopuls-Radars gezeigt

A review of management strategies for salt-prone land and water resources in Iran

Water resource management/ Land management/ Leaching/ Drainage/ Sodic soils/ Soil reclamation/ Supplemental irrigation/ Irrigation programs

The role of rainfed agriculture in the future of global food production:

This paper examines future prospects for rainfed cereal production, and its importance in the evolving global food system. First, the paper undertakes a critical synthesis of the literature to assess three primary ways to enhance rainfed cereal yields: increasing effective rainfall use through improved water management, particularly water harvesting; increasing crop yields in rainfed areas through agricultural research; and reforming policies and increasing investments in rainfed areas. Second, the IMPACT-WATER integrated water-food modeling framework is applied to assess the current situation and plausible future options of irrigation water supply and food security, primarily on a global scale. This model simulates the relationships among water availability and demand, food supply and demand, international food prices, and trade at regional and global levels. The results show that rainfed agriculture will maintain an important role in the growth of food production in the future, although appropriate investments and policy reforms will be required to enhance the contribution of rainfed agriculture.Agricultural policy., Rainfed farming Developing countries., Cereal crops. Agricultural policy., Rainfed farming Developing countries., Cereal crops., Food security., Water-supply., Food supply., Trade., Crop yields., Water use Management.,

Anthropogenic impacts on recharge processes and water quality in basin aquifers of the desert Southwest : a coupled field observation and modeling study

textThe development of natural grass/scrubland for agricultural use within the Trans-Pecos basins has altered recharge mechanisms and raised questions about groundwater sustainability. Past efforts focused on recharge in arid basin systems used three main assumptions: there is minimal modern recharge, no widespread recharge on basin floors, and no recharge from anthropogenic sources. However, in the Trans-Pecos, nitrate (NO₃-) concentrations have increased in basin groundwater (up by 3-4 mg/l as NO₃- in 40 yrs), refuting the “classic” model and posing water quality risks. Grazing and irrigated agriculture have impacted basin hydrology by altering vegetation regime and the magnitude and spatial distribution of infiltration. This has increased recharge, Cl⁻, and mobile N flux to basin groundwater. A series of spatially-distributed net infiltration models were used to estimate potential recharge from natural and anthropogenic sources. Between 7-20% of potential recharge results from widespread recharge on the basin floors. Additionally, from 1960-2000, irrigation return flow may have contributed 3.0 × 10⁷ - 6.3 × 10⁷ m³ of recharge. These results are supported by field observations. Cores collected beneath agricultural land document changes in water content and pore water chemistry that imply increased downward flux of moisture and solute, and NO₃- and Cl- inventories beneath irrigated land are distinct in amount and profile from those in natural areas. There are significant implications for sustainability based upon the trends in groundwater NO₃- concentrations, core results, and net infiltration models: more recharge may enter the basins than previously estimated and there is a potential long-term concern for water quality. Due to thick unsaturated zones in the basins, long travel times are anticipated. It is unknown if NO3- and Cl⁻ flux has peaked or if effects will continue for years to come. Further study should be undertaken to examine anthropogenic impacts on basin water quality. Additionally, these impacts may occur in similar systems globally and there is considerable evidence for the re-evaluation of the validity of the “classic” model of recharge in arid basin systems. Future studies and management plans should incorporate potential impacts of changes in vegetation and land use on recharge processes and water budgets in arid basins.Geological Science

Water management under scarcity and climate change: methodological proposals and analysis of policy instruments

Esta tesis aborda algunos de los desafíos más importantes en relación a los recursos hídricos de las zonas áridas y semiáridas. Estos desafíos incluyen la creciente escasez de agua, los impactos del cambio climático, y la degradación generalizada de los ecosistemas acuáticos. Los cuatro capítulos principales presentan el desarrollo de distintos métodos de modelización hidroeconómica que integran aspectos hidrológicos, económicos, institucionales y medioambientales, y que se aplican al caso de la cuenca del Júcar en España. Los capítulos ofrecen una descripción detallada del proceso de modelización, los análisis realizados, y las principales conclusiones e implicaciones. Sin embargo, los modelos también pueden aplicarse a otras cuencas de las zonas áridas y semiáridas. Las metodologías desarrolladas en esta tesis representan un conjunto de herramientas muy prometedoras para realizar análisis integrados de los escenarios climáticos y de política de agua. Los resultados obtenidos proporcionan información útil para el diseño de políticas de gestión sostenible de los recursos hídricos. En esta tesis se consideran varios métodos para mejorar los modelos de análisis de la política de agua. Estos avances metodológicos están relacionados con el proceso de integración de las diferentes dimensiones de los recursos hídricos, la mejora de los aspectos estocásticos y dinámicos de los modelos, y la inclusión del comportamiento estratégico de los grupos de interés. No existen muchos estudios en la literatura que consideren conjuntamente las cuestiones de modelización y de implementación de las políticas de agua. Los resultados empíricos muestran el potencial de los modelos hidroeconómicos integrados para evaluar los impactos económicos y medioambientales de las políticas de agua bajo distintos escenarios climáticos. La modelización parcial basada solamente en las relaciones económicas, pero sin un fundamento biofísico sólido, no pueden determinar con rigor estos impactos que son importantes para la toma de decisión en la gestión de los recursos hídricos. Los resultados de esta tesis tienen implicaciones políticas importantes porque muestran las dificultades para lograr una gestión más sostenible de los recursos hídricos en las regiones áridas y semiáridas. La toma de decisiones es compleja para poder resolver los impactos de la escasez de agua, las sequías y el cambio climático en las actividades económicas y los ecosistemas de las cuencas. Los gobiernos pueden implementar varias políticas para mitigar dichos impactos, tales como la promoción de la gestión cooperativa de los recursos hídricos, facilitar la implementación de mercados de agua, y proporcionar incentivos económicos para el ahorro del agua. Sin embargo, los decisores políticos deben ser conscientes de las consecuencias adversas de la mala planificación hídrica, como son los impactos medioambientales negativos. También deben considerar la aceptabilidad de las políticas por los grupos de interés, para evitar el fracaso de las políticas