Doctoral Dissertation Research: Understanding Intermittent Water Sources and Impacts on Fish to Design Optimal Water Conservation Strategies

水资源方面的一个主要问题是，如何在为人类提供用水的同时，维持维持河流生态系统和渔业的流量。间歇性的溪流为鲑鱼提供栖息地，为农业提供水资源，在夏末干涸成一系列不相连的池塘。为了减轻对河流的压力，保护濒临灭绝的幼鲑鱼的栖息地，社区越来越多地研究水资源保护的替代方案，如雨水收集和地下水补给。最近的试点项目提供了一个及时和前所未有的机会，以解决有关环境变量之间的联系，生态系统服务，和优化管理日益稀缺的水资源的跨学科问题。该项目有望为基础科学做出新的贡献，包括理解与鱼类生存相关的过程以及间歇性河流中碳分解、径流和沉积物输运之间的相互作用。通过将鲑鱼生存与可预测的环境特征联系起来，并更好地了解这些关键变量，研究结果可能适用于区域和全国范围内的季节性干旱流域。该项目将促进科学家和多个利益攸关方群体之间的互利互动，这些群体也将受益于管理其自然资源的新电子工具。调查结果将通过学术出版物和区域研讨会以及通过为利益相关者和公民科学门户网站编写的文件传播。该项目专门解决了一个基本的知识差距：什么样的栖息地条件导致鲑鱼在夏季干旱期间从一些水池中消失？该项目建立在鲑鱼溪（索诺马公司，CA）：整个夏天都在流动的Tannery Creek和Fay Creek，后者往往会干涸成一系列孤立的水池。通过在这些相邻的溪流中进行广泛的采样，这项研究将测试这样一个假设，即在冲洗不良的水池中有机物质的积累会导致溶解氧下降，从而导致鲑鱼的损失。两条支流的鱼类调查将与温度、溶解氧、水深和流速、游泳池体积以及有机碳浓度和质量的测量相结合。将在四个研究河段进行更深入的研究，重点是监测这些属性如何随着河流干涸而变化，并确定哪些含水层维持避难池。使用线性混合模型，这项研究将量化地下水的贡献和流动路径池，提供关键的避难所鲑鱼，并确定含水层，应加强渗透的目标。这项工作还将评估雨水收集将如何影响鲑鱼栖息地与管理地下水补给。作为博士论文研究改进奖，该项目将提供支持，使有前途的学生建立一个独立的研究生涯。提高对地下水和径流之间相互作用的认识，将使居民和资源保护区能够针对水源保护和雨水收集项目，这些项目将为河流生态系统带来最大利益。致力于鲑鱼恢复的科学家将通过促进合作研讨会和项目开发的公民科学传播工具，从更多的地方知识和观察中受益。

A major question in water resources is how to provide water for human uses while maintaining streamflow that sustains riverine ecosystems and fisheries. Intermittent streams, which provide habitat for salmonid fishes and water resources for agriculture, dry up into a series of disconnected pools in the late summer. To alleviate pressure on rivers and conserve habitat for juvenile salmon on the brink of extinction, communities are increasingly examining water conservation alternatives such as rainwater harvesting and groundwater recharge. Recent pilot projects provide a timely and unprecedented opportunity to address interdisciplinary questions about linkages among environmental variables, ecosystem services, and optimal management of increasingly scarce water resources. This project is expected to produce novel contributions to fundamental science, including understanding processes related to fish survival and the interactions among carbon decomposition, streamflow, and sediment transport in intermittent streams. By relating salmonid survival to predictable environmental characteristics and creating a better understanding of these critical variables, the research findings are likely to have applicability to seasonally dry watersheds region-and nation-wide. The project will facilitate mutually beneficial interactions between scientists and multiple stakeholder groups, who will also benefit from new e-tools for managing their natural resources. Findings will be disseminated through scholarly publications and at regional symposia as well as through documents developed for stakeholders and a citizen science web portal.This project specifically addresses a fundamental knowledge gap: what habitat conditions cause salmonids to disappear from some pools during the summer dry period? This project builds on a two-year field study in two tributaries of Salmon Creek (Sonoma Co., CA): Tannery Creek, which flows throughout the summer, and Fay Creek, which tends to dry into a series of isolated pools. Through extensive sampling in these adjacent streams, this research will test the hypothesis that accumulation of organic material in poorly flushed pools drives declining dissolved oxygen associated with a subsequent loss of salmonids. Fish surveys in the two tributaries will be paired with measurements of temperature, dissolved oxygen, water depth and velocity, pool volume, and organic carbon concentrations and quality. More intensive studies, focused on monitoring how these attributes change as the stream dries and determining which aquifers sustain sanctuary pools, will be conducted in four study river segments. Using linear mixing models, this research will quantify groundwater contributions and flowpaths to pools that provide critical refugia for salmon, and identify aquifers that should be targeted for enhanced infiltration. This work will also evaluate how rainwater harvesting will impact salmonid habitat with and without managed groundwater recharge. As a Doctoral Dissertation Research Improvement award, this project will provide support to enable a promising student to establish an independent research career. Increased understanding of interactions between groundwater and streamflow will enable residents and resource conservation districts to target water conservation and rainwater harvesting projects where they will yield the greatest benefit to stream ecosystems. Scientists working on salmonid recovery will benefit from increased access to local knowledge and observations via facilitated collaborative workshops and project-developed citizen science dissemination tools.