柳州市地表水质量评价及生态治理研究

Study on the Quality Assessment and Ecological Governance of Surface Water in Liuzhou City

摘要: 为评价柳州市典型地表水断面的水环境质量并提出生态治理路径，本研究设置柳江上游来水、市区景观河段、工业影响控制、支流入江口和水源保护相关5类典型断面，在2024年5~9月平水期至丰水期开展监测，选取pH、DO、CODMn、COD、NH₃-N、TP和TN等指标，依据GB 3838-2002采用单因子评价法和综合污染指数法分析水质类别、污染压力及主控因子，并结合底泥污染和水生态风险指标开展补充分析。结果表明，断面水质总体处于II~III类，上游来水和水源保护相关断面水质较好，支流入江口综合污染指数最高(P = 0.87)，TN、TP和NH₃-N为主要影响因子；工业影响控制断面COD和CODMn相对偏高，说明有机污染输入和工业排水风险仍需持续监管。底泥及水生态辅助指标显示，支流入江口和工业影响河段存在营养盐累积及生境质量下降风险。建议从源头控污、重点支流治理、排污口监管、生态缓冲带建设、水生态修复和智慧监测预警等方面推进分区治理。研究可为柳州市优良水质保持及工业城市水生态治理提供参考。

Abstract: To evaluate the water environmental quality of typical surface-water sections in Liuzhou City and to propose ecological governance strategies, five representative sections were selected, including upstream inflow, urban landscape reach, industrial impact reach, tributary confluence and water-source protection reach. Monitoring was conducted from May to September 2024, covering the normal and wet seasons. The indicators of pH, DO, CODMn, COD, NH₃-N, TP and TN were analyzed using the single-factor method and comprehensive pollution index according to GB 3838-2002. Sediment pollution and aquatic ecological risk indicators were also included as supplementary evidence. The results show that the water quality of the typical sections was generally Class II-III. The upstream inflow and water-source protection sections had better conditions, while the tributary confluence section had the highest comprehensive pollution index (P = 0.87), with TN, TP and NH₃-N as the dominant factors. COD and CODMn were relatively higher in the industrial impact section, indicating continued risks of organic pollution and industrial discharge. The supplementary sediment and ecological indicators suggested nutrient accumulation and habitat degradation risks in the tributary confluence and industrial impact reaches. Integrated governance measures, including source control, tributary treatment, outfall supervision, ecological buffer zones, aquatic ecological restoration and intelligent monitoring, are recommended. This study provides references for maintaining good water quality and improving ecological governance in industrial cities.