Data from: Restoration as mitigation: analysis of stream mitigation for coal mining impacts in southern Appalachia

Compensatory mitigation is commonly used to replace aquatic natural resources being lost or degraded but little is known about the success of stream mitigation. This article presents a synthesis of information about 434 stream mitigation projects from 117 permits for surface mining in Appalachia. Data from annual monitoring reports indicate that the ratio of lengths of stream impacted to lengths of stream mitigation projects were < 1 for many projects, and most mitigation was implemented on perennial streams while most impacts were to ephemeral and intermittent streams. Regulatory requirements for assessing project outcome were minimal; visual assessments were the most common and 97% of the projects reported suboptimal or marginal habitat even after 5 years of monitoring. Less than a third of the projects provided biotic or chemical data; most of these were impaired with biotic indices below state standards and stream conductivity exceeding federal water quality criteria. Levels of selenium known to impair aquatic life were reported in 7 of the 11 projects that provided Se data. Overall, the data show that mitigation efforts being implemented in southern Appalachia for coal mining are not meeting the objectives of the Clean Water Act to replace lost or degraded streams ecosystems and their functions.

补偿性缓解措施（compensatory mitigation）通常被用于替代丧失或退化的水生自然资源，但目前学界对河流补偿项目的实施成效仍知之甚少。本文对来自阿巴拉契亚地区117份露天采矿许可相关的434个河流补偿项目的相关信息进行了综合梳理。年度监测报告数据显示，多数项目中受影响河流长度与补偿河流长度的比值小于1；且多数补偿项目设置于常年性河流，而多数受影响的河流则为暂时性与间歇性河流。项目成效评估的监管要求极低，视觉评估是最常用的评估方式；即便经过5年监测，仍有97%的项目报告其栖息地处于次优或边缘状态。仅不到三分之一的项目提供了生物或化学监测数据，其中多数项目存在生态受损情况：生物指数低于州立标准，河流电导率超出联邦水质标准限值。在提供硒（Se）监测数据的11个项目中，有7个项目报告了已知会损害水生生物的硒浓度水平。总体而言，数据表明，阿巴拉契亚南部地区为煤炭开采实施的河流补偿项目，未能达到《清洁水法》中关于替代丧失或退化河流生态系统及其功能的目标要求。