Abstract

Burnet SH, Wilhelm FM. 2021. Estimates of internal loading of phosphorus in a western US reservoir using 3 methods. Lake Reserv Manage. 37:261–274.

We used 3 methods to estimate internal loading of total and dissolved phosphorus (TP/DP) in 2 years in a stratified eutrophic western US reservoir with high internal loading of phosphorus. We calculated the internal load from (i) net increases of TP/DP from reservoir water column samples, (ii) gross TP mass balances, and (iii) gross TP/DP loading estimated from laboratory-incubated sediment cores and the anoxic reservoir area. We also present a cost comparison and spreadsheet to allow managers to estimate costs for each method. The highest internal loads were estimated in 2015 from the net in situ samples (999 mg/m²/yr) and the gross annual mass balance (850 mg/m²/yr). Gross estimates from sediment cores were 1.2× higher in 2015 than in 2014 due to differences in anoxic area resulting from a drought and record reservoir drawdown. Costs were highest for the mass balance method and lowest for the sediment core method. Given the small monetary difference between the sediment core and in situ methods, we suggest managers obtain in situ data to estimate internal loading because this yields a net estimate most reflective of whole-lake dynamics. Our data provide an important benchmark of internal loading in a human-made reservoir given the general paucity of such estimates in this large geographic region.

摘要

伯内特 SH，威廉 FM。2021. 使用 3 种方法估计美国西部水库中磷的内部负荷。湖泊保护区管理。37:261-274。

我们使用 3 种方法估算了美国西部分层富营养化水库中 2 年内总磷和溶解磷 (TP/DP) 的内部负荷，其中磷的内部负荷很高。我们从 (i) 来自水库水柱样本的 TP/DP 的净增加，(ii) 总 TP 质量平衡，以及 (iii) 从实验室培养的沉积物核心和缺氧库区估计的总 TP/DP 负载计算内部负荷. 我们还提供了成本比较和电子表格，以便管理人员能够估算每种方法的成本。2015 年根据净原位样品 (999 mg/m ² /yr) 和年度总质量平衡 (850 mg/m ²/年）。由于干旱和创纪录的水库下降导致缺氧区域的差异，2015 年沉积物岩心的总估计值比 2014 年高 1.2 倍。质量平衡方法的成本最高，沉积物核心方法的成本最低。鉴于沉积物核心和原位方法之间的货币差异很小，我们建议管理人员获取原位数据来估计内部负荷，因为这会产生最能反映整个湖泊动态的净估计值。我们的数据提供了一个重要的人工水库内部负荷基准，因为在这个大的地理区域内这种估计普遍缺乏。