Evaluation of constraints to water quality improvements in the Western Lake Erie Basin.
Evaluation of constraints to water quality improvements in the Western Lake Erie Basin.
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DOI：
10.1016/j.jenvman.2017.09.063
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发表时间：
2018
影响因子：
8.7
通讯作者：
Lawrence Sekaluvu;Lefei Zhang;M. Gitau
中科院分区：
文献类型：
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作者：
Lawrence Sekaluvu;Lefei Zhang;M. Gitau
由于富营养化和有害藻类水华的扩散，西湖伊利盆地(WLEB)经历了严重的环境和健康影响。几十年来，改善世界水利枢纽内的水质的努力一直在进行。然而，流域的水质改善并没有像预期的那样实现。在这项研究中，评估了影响WLEB内水质的因素，以期区分它们的影响，并为进一步的评估提供信息。在长期(1966-2015年)和全流域范围内，年总降水量显著增加约2.4亿毫米/年，而同期月平均径流量也增加，尽管增加幅度不大(p=0.36)。然而，在此期间，春季径流显著增加(p=0.003)。水质参数模式显示，总悬浮固体(TP)(P=0.001)和总磷(TP)显著下降(P=0.018)，而可溶性活性磷(S R P)显著增加(P=0.001)，特别是从1995年左右开始。近期(2005年至2015年)的分析结果显示，悬浮固体浓度没有显著(p=0.262)下降，约为0.25亿mg/L/年。在同一时期，TP浓度变化不大，而硝酸盐浓度增加了0.11亿mg/L/年，SRP增加了0.001 mg/L/年，其中硝酸盐浓度的增加是显著的(p=0.013)。然而，流域内TP和SRP的浓度仍然很高，日变化范围分别为0.03~1.84m g/L和0.002~0.52m g/L。在整个流域范围内，2005年至2015年期间，春季降水量和春季径流都显著增加(p<0.001)。总体而言，没有观察到土地利用的实质性变化，这表明水质反应可能归因于管理。根据近期数据，流域玉米种植面积和玉米施肥量分别增加33%和10%。混合下水道溢流和蓄水也是重要因素，因为它们在盆地中普遍存在。根据分析，农业管理的变化、春季降雨量的增加、民间社会组织、遗留磷以及大坝的存在被认为是制约水质改善的因素，尽管流域内进行了保护努力。
Severe environmental and health impacts have been experienced in the Western Lake Erie Basin (WLEB) because of eutrophication and associated proliferation of harmful algae blooms. Efforts to improve water quality within the WLEB have been on-going for several decades. However, water quality improvements in the basin have not been realized as anticipated. In this study, factors affecting water quality within the WLEB were evaluated with a view to differentiating their impacts and informing further assessments in the basin. Over the long-term (1966–2015) and basin-wide, total annual precipitation increased significantly by about 2.4 mm/year while mean monthly streamflows also increased during the same period although the increase was not significant (p = 0.36). There was, however, a significant increase in spring streamflows during this period (p = 0.003). Patterns in water quality parameters showed significant reductions in total suspended solids (TSS) (p < 0.001) and total phosphorus (TP) (p = 0.018) while soluble reactive phosphorus (SRP) increased significantly (p < 0.001), and in particular from about 1995. Results of near-term (2005–2015) analysis showed a non-significant (p = 0.262) reduction in TSS concentrations of about 0.25 mg/L/year. TP concentrations did not vary substantially during the same period while a 0.11 mg/L/year increase in nitrate and a 0.001 mg/L/year increase in SRP were observed, with increases in nitrates being significant (p = 0.013). TP and SRP concentrations, however, remained high within the basin with daily values ranging between 0.03 and 1.84 mg/L and less than 0.002–0.52 mg/L, respectively. Basin-wide, both spring precipitation and spring streamflows increased significantly during the period 2005–2015 (p < 0.001). Overall, no substantial changes in land use were observed, suggesting that water quality responses might be attributable to management. Based on recent data, corn acreage in the basin and fertilizer applied to corn increased by 33% and 10% respectively. Combined Sewer Overflows (CSOs) and impoundments were also important factors due to their prevalence in the basin. Based on the analysis, changes in agricultural management, increase in spring precipitation, CSOs, legacy phosphorus, and the presence of dams were thought to present constraints to water quality improvements despite conservation efforts within the basin.