Department of Civil and Environmental Engineering, University of Maryland, College Park, MD, USA.
Roadway Business Line, Gannett Fleming, Inc., Baltimore, MD, USA.
Environ Monit Assess. 2023 Mar 10;195(4):460. doi: 10.1007/s10661-023-11070-7.
Sunlight plays a key role in the nutrient cycle within streams. Streams are often piped to accommodate urban residential or commercial development for buildings, roads, and parking. This results in altered exposure to sunlight, air, and soil, subsequently affecting the growth of aquatic vegetation, reducing reaeration, and thus impairing the water quality and ecological health of streams. While the effects of urbanization on urban streams, including changing flow regimes, stream bank and bed erosion, and degraded water quality, are well understood, the effects of piping streams on dissolved oxygen (DO) concentrations, fish habitats, reaeration, photosynthesis, and respiration rates are not. We addressed this research gap by assessing the effects of stream piping on DO concentrations before and after a 565-m piped section of Stroubles Creek in Blacksburg, VA, for several days during the summer of 2021. Results indicate that the DO level decreased by approximately 18.5% during daylight hours as water flowed through the piped section of the creek. Given the optimum DO level (9.0 mg·L) for brook trout (Salvelinus sp.), which are native and present in a portion of Stroubles Creek, the resulting DO deficits were - 0.49 and - 1.24 mg·L, for the inlet and outlet, respectively, indicating a possible adverse impact from piping the stream on trout habitat. Photosynthesis and respiration rates were reduced through the piped section, primarily due to the reduced solar radiation and the resultant reduction in oxygen production from aquatic vegetation; however, the reaeration rate increased. This study can inform watershed restoration efforts, particularly decisions regarding stream daylighting with respect to potential water quality and aquatic habitat benefits.
阳光在溪流的养分循环中起着关键作用。溪流通常被管道化以适应城市住宅或商业开发，用于建筑物、道路和停车场。这导致阳光、空气和土壤的暴露发生变化，从而影响水生植被的生长，减少再曝气，从而损害溪流的水质和生态健康。虽然城市化对城市溪流的影响，包括改变水流模式、溪岸和河床侵蚀以及水质恶化，已经得到很好的理解，但管道化溪流对溶解氧（DO）浓度、鱼类栖息地、再曝气、光合作用和呼吸率的影响却没有得到很好的理解。我们通过评估弗吉尼亚州布莱克斯堡的斯特鲁布尔斯溪（Stroubles Creek）一段 565 米长的管道化溪流在 2021 年夏天的几天内前后的 DO 浓度来填补这一研究空白。结果表明，当水流经溪的管道化部分时，DO 水平在白天下降了约 18.5%。考虑到溪鳟鱼（Salvelinus sp.）的最佳 DO 水平（9.0 mg·L），溪鳟鱼是斯特鲁布尔斯溪的一部分，原生且存在于溪中，因此，在入口和出口处的 DO 亏缺分别为-0.49 和-1.24 mg·L，表明管道化溪流对鳟鱼栖息地可能产生不利影响。通过管道化部分，光合作用和呼吸率降低，主要是由于太阳辐射减少，以及水生植被产生的氧气减少；然而，再曝气率增加。本研究可以为流域恢复工作提供信息，特别是在考虑溪流日光照明对潜在水质和水生栖息地效益的决策方面。
