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

Runoff generation, infiltration dynamics, and recharge across multiple scales: Applications for improving groundwater supply and quality

Groundwater is a critical resource facing declining supply and quality around the world. Distributed stormwater collection coupled with managed aquifer recharge (DSC-MAR) is a developing strategy to enhance groundwater recharge by collecting excess hillslope runoff in infiltration basins. DSC-MAR projects provide opportunities to learn about the inter-related hydrologic processes of runoff generation, infiltration, and recharge in the context of sustainable groundwater management. The three chapters presented here use interdisciplinary approaches to study these processes at multiple scales, including (1) regional computer models evaluating the impact of shifting climate and land use on runoff generation and recharge, (2) multi-year field observations quantifying the dynamics of runoff generation and infiltration, and (3) field-based experiments linking hydrologic, geochemical, and microbial processes during rapid infiltration. In Chapter 1, models suggest that urban and agricultural development reduce the threshold for runoff generation relative to pre-development land use, resulting in up to 2.3 times as much runoff and less recharge basin-wide. When incorporated into an MAR suitability map combining soil, bedrock, and aquifer properties, model results demonstrate that DSC-MAR projects could be effective in many locations during a range of climate scenarios. Field results from Chapter 2 show that a pilot DSC-MAR project was successful, collecting and infiltrating 5.3 × 105 m3 (426 ac-ft) over six years, including an extended regional drought. Runoff generation was sensitive to sub-daily storm frequency, duration, and intensity; observed infiltration rates varied widely in space and time; and 8.2 × 105 kg of fine-grained sediment accumulated in the infiltration basin over three years, likely reducing soil infiltration capacity. In Chapter 3, soils below a horizontal permeable reactive barrier (PRB) made of woodchips had greater nitrate removal (1.5 g/m2/day NO3-N) than un-amended native soils (0.09 g/m2/day NO3-N), despite rapid infiltration up to 1.9 m/d. Many putative denitrifying bacteria were enhanced in soils below the PRB. A PRB seemed to create favorable conditions for denitrification in underlying soils and could be applied to improve water quality during DSC-MAR. Collectively, the results of these studies advance our understanding of fundamental hydrologic processes and inform strategies to improve groundwater supply and quality

Aspectos morfologicos das fibras intrafusais do musculo deltoide em pacientes com distrofia muscular de Duchenne/Becker

As distrofias musculares de Duchenne e Becker, (DmD/DmB) consistem em um disturbio genetico acometendo o braco curto do cromossomo X. O produto genetico desta alteracao e a distrofina que se encontra ausente nesses pacientes. No presente trabalho, enfocamos o estudo morfologico dos fusos neuromusculares em pacientes portadores desta miopatia, cadastrados no Ambulatorio de Doencas Neuromusculares da Disciplina de Neurologia da Universidade Federal de São Paulo - Escola Paulista de Medicina. As biopsias musculares foram realizadas a partir do musculo deltoide segundo tecnica amplamente difundida. Utilizamos neste estudo tecnicas histologicas de rotina tais como, hematoxilina e eosina (H.E), adenosina trifosfato (ATP) e tetrazolium redutase (NADH). Foram avaliadas as caracteristicas morfologicas do fuso neuromuscular, bem como sua estrutura interna, numero de camadas da capsula do fuso, vasos sanguineos no interior do mesmo e a presenca de macrofagos. Atraves dos procedimentos acima citados identificamos fibras intrafusais do tipo I e II, bem como pudemos observar que as alteracoes histologicas do fuso neuromuscular em relacao as fibras extrafusais foram semelhantes, concluindo que ocorre um comprometimento universal tanto para as fibras intrafusais como extrafusaisBV UNIFESP: Teses e dissertaçõe

Coupling distributed stormwater collection and managed aquifer recharge: Field application and implications.

Groundwater is increasingly important for satisfying California's growing fresh water demand. Strategies like managed aquifer recharge (MAR) can improve groundwater supplies, mitigating the negative consequences of persistent groundwater overdraft. Distributed stormwater collection (DSC)-MAR projects collect and infiltrate excess hillslope runoff before it reaches a stream, focusing on 40-400 ha drainage areas (100-1000 ac). We present results from six years of DSC-MAR operation-including high resolution analyses of precipitation, runoff generation, infiltration, and sediment transport-and discuss their implications for regional resource management. This project generated significant water supply benefit over six years, including an extended regional drought, collecting and infiltrating 5.3 × 105 m3 (426 ac-ft). Runoff generation was highly sensitive to sub-daily storm frequency, duration, and intensity, and a single intense storm often accounted for a large fraction of annual runoff. Observed infiltration rates varied widely in space and time. The basin-average infiltration rate during storms was 1-3 m/d, with point-specific rates up to 8 m/d. Despite efforts to limit sediment load, 8.2 × 105 kg of fine-grained sediment accumulated in the infiltration basin over three years, likely reducing soil infiltration capacity. Periodic removal of accumulated material, better source control, and/or improved sediment detention could mitigate this effect in the future. Regional soil analyses can maximize DSC-MAR benefits by identifying high-infiltration capacity features and characterizing upland sediment sources. A regional network of DSC-MAR projects could increase groundwater supplies while contributing to improved groundwater quality, flood mitigation, and stakeholder engagement