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| 小流域沟塘面源消纳方程构建及成本效益优化研究 |
| Construction of Nutrient Attenuation Equations for Ditches and Ponds in Small Watersheds and Their Cost–Benefit Optimization |
| 投稿时间：2025-11-25 修订日期：2026-01-30 |
| DOI： |
| 中文关键词: 沟渠 水塘 面源污染 消纳方程 氮磷 措施优化 |
| 英文关键词: ditches ponds non-point source pollution attenuation equations nitrogen and phosphorus measure optimization |
| 基金项目:国家重点研发计划(2024YFD1701303)；国家自然科学基金青年科学(42507073)；长江水科学研究联合基金(U2340219) |
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| 中文摘要: |
| 针对流域尺度面源模型中对沟渠和水塘采用简化方程评估其消纳能力，导致较大评价不确定性进而制约了小流域沟塘优化布局的问题，本研究整合了近50年来217组沟塘实测数据，构建了涵盖全国不同气候与地形区的沟塘消纳数据库，进而系统识别了影响面源氮、磷消纳的关键因子，结合机器学习与多元非线性方法建立了沟渠和水塘的氮磷消纳方程。结果表明：沟渠植被覆盖度、水力停留时间及高度是主要影响因子，消纳过程呈现明显的“阈值效应”与“边际递减”特征；当植被覆盖度大于30%、水力停留小于50h的时候总氮消纳效率最高，高度大于1.0 m时总磷消纳率最高；水塘深0.6~0.8m、水力停留小于150h消纳效果最佳。将新建方程嵌入已有模型，总氮、总磷模拟精度较高（R2大于0.58且NSE均大于0.5），表明新方程具有良好适用性。成本效益优化表明，当沟塘植被覆盖度提升15%，且沟渠长度增加15%时，可在较低成本下显著提升面源氮、磷消纳效果。 |
| 英文摘要: |
| To address the large uncertainty in watershed-scale nonpoint source pollution models caused by simplified representations of nutrient retention in ditches and ponds, which constrains the optimization of ditch–pond configurations in small catchments, this study compiled 217 sets of field-measured retention data from the past 50 years to establish a national ditch–pond nutrient retention database covering diverse climatic and topographic regions. Key factors controlling nitrogen (N) and phosphorus (P) retention were systematically identified, and machine learning combined with multivariate nonlinear methods was used to develop explicit retention equations for ditches and ponds. The results indicate that vegetation cover, hydraulic residence time, and structure height are the dominant factors controlling retention in ditch systems, with clear threshold and marginal diminishing effects. Total nitrogen retention reaches its optimum when vegetation cover exceeds 30% and hydraulic residence time is less than 50 h, while total phosphorus retention is maximized when ditch height exceeds 1.0 m. For pond systems, optimal N and P retention occurs at water depths of 0.6–0.8 m with hydraulic residence times shorter than 150 h. When embedded into an existing distributed watershed model, the newly developed equations yield good simulation performance for total nitrogen and total phosphorus (R2 > 0.58 and NSE > 0.5), demonstrating their applicability. Cost-effectiveness optimization further shows that increasing ditch–pond vegetation cover by 15% and ditch length by 15% can substantially enhance nitrogen and phosphorus retention at relatively low implementation costs. |
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