Effects of small freshwater inflow volumes on water and sediment quality obtained from bays in Texas from 2015-09-30 to 2016-09-15

This study contains data showing effects of small freshwater inflow volumes on water and sediment quality obtained from bays in Texas, specifically Lavaca-Colorado and Guadalupe estuaries, from to 2015-09-30 to 2016-09-15. The aim of this study was to quantify the effects of small changes of inflow volumes on ecosystem health to evaluate the potential environmental benefits of hydrological conservation or restoration projects. Discharge, water quality (indicated by nutrients and chlorophyll), and sediment quality (indicated by benthic communities) were sampled monthly at five stations in the upper reaches of the Guadalupe and Lavaca-Colorado estuaries. Distinct oligohaline and mesohaline benthic communities were present in both estuaries. Flow discharge, water quality, and benthic metrics were correlated. The positive correlation between multivariate water quality parameters, and benthic metrics indicates a positive relationship between small flow changes and estuarine health. The Guadalupe estuary had a 92% higher mean monthly freshwater inflow rate than the Lavaca-Colorado estuary, thus a larger flow volume increase was necessary to affect estuarine health in the Guadalupe estuary. This analysis indicated that a small volume, as low as 10% of freshwater inflow volume, can have positive benefits to estuarine conditions and health. Thus, hydrological protection or restoration projects based on small volumes can improve estuaries degraded by freshwater diversions.

本研究包含的数据集揭示了小型淡水入流量对水体与沉积物质量的影响，数据采集自美国得克萨斯州的拉瓦卡-科罗拉多（Lavaca-Colorado）与瓜达卢佩（Guadalupe）河口湾，采样时段为2015年9月30日至2016年9月15日。本研究旨在量化入流量小幅变化对生态系统健康的影响，以评估水文保护或修复工程的潜在环境效益。研究团队在瓜达卢佩河口与拉瓦卡-科罗拉多河口的上游区域共设置5个监测站位，每月对径流量、水质（以营养盐与叶绿素为表征指标）以及沉积物质量（以底栖生物群落为表征指标）进行采样。两个河口均存在特征鲜明的寡盐（oligohaline）与中盐（mesohaline）底栖生物群落。径流量、水质与底栖生物群落指标之间存在显著相关性。多参数水质指标与底栖生物群落指标之间的正相关关系，表明径流量小幅变化与河口健康状态之间存在正向关联。瓜达卢佩河口的月均淡水入流量较拉瓦卡-科罗拉多河口高出92%，因此要影响瓜达卢佩河口的健康状态，需要更大幅度的径流量增量。本分析结果显示，仅需相当于原淡水入流量10%的小型增量，即可对河口环境与健康状态产生积极效益。因此，基于小型入流量增量的水文保护或修复工程，能够改善因淡水分流而退化的河口生态系统。