Sediments and nutrients input to a small reservoir in the tropical semi-arid region

ABSTRACT The sediment and nutrients that are input to surface reservoirs compromise the quality and quantity of the stored water. The aim of this study was to investigate the dynamics of sediment and nutrient input along the drainage basin of a small reservoir in the semi-arid region. The reservoir under study was built in 1956 and has a storage capacity of 5.01 hm3. Seven trenches were dug along the drainage basin of the reservoir following the river. Sediment samples were collected at increasing depths of 20 cm until reaching the original riverbed. An analysis of particle size, total organic carbon (TOC), total nitrogen (TN), available phosphorus (P), exchangeable aluminium (Al), total iron (TFe) and pH was carried out. Approximately 60% of the sediment in the reservoir is composed of clay and silt, and 40% of sand. The greatest thickness of the sediment layer, as well as the greatest concentration of fine sediment, was registered in the section nearest to the dam. The values for TOC (2.47 < TOC < 34.47 g kg-1) and TN (0.69

摘要：输入至地表水库的沉积物与营养物质，会损害储水的品质与储量。本研究旨在探究半干旱区域某小型水库流域内沉积物与营养物质输入的动态变化规律。本次研究的水库始建于1956年，总库容为5.01 hm³。研究团队沿水库流域的河道布设了7条探槽，以每20 cm为间隔采集沉积物样品，直至原始河床。对采集的样品开展了粒度分析、总有机碳（Total Organic Carbon, TOC）、总氮（Total Nitrogen, TN）、有效磷（Available Phosphorus, P）、交换性铝（Exchangeable Aluminium, Al）、总铁（Total Iron, TFe）以及pH值的测定分析。水库沉积物中约60%为黏土与粉砂组分，40%为砂质组分。沉积物层最大厚度以及细粒沉积物最高浓度均出现在紧邻大坝的区域。总有机碳（TOC）取值范围为2.47 < TOC < 34.47 g·kg⁻¹，总氮（TN）取值范围为0.69