Summary Reliable runoff estimation is important for design of water infrastructure and flood risk management in urban catchments. We developed a spatially distributed Precipitation-Runoff (P-R) model that explicitly represents the land cover information, performs integrated modelling of surface and subsurface components of the urban precipitation water cycle and flow routing. We conducted parameter calibration and validation for a small (21.255 ha) stormwater catchment in Trondheim City during Summer-Autumn events and season, and snow-influenced Winter-Spring seasons at high spatial and temporal resolutions of respectively 5 m × 5 m grid size and 2 min. The calibration resulted in good performance measures (Nash-Sutcliffe efficiency, NSE = 0.65–0.94) and acceptable validation NSE for the seasonal and snow-influenced periods. The infiltration excess surface runoff dominates the peak flows while the contribution of subsurface flow to the sewer pipes also augments the peak flows. Based on the total volumes of simulated flow in sewer pipes (Qsim) and precipitation (P) during the calibration periods, the Qsim/P ranges from 21.44% for an event to 56.50% for the Winter-Spring season, which are in close agreement with the observed volumes (Qobs/P). The lowest percentage of precipitation volume that is transformed to the total simulated runoff in the catchment (QT) is 79.77%. Computation of evapotranspiration (ET) indicated that the ET/P is less than 3% for the events and snow-influenced seasons while it is about 18% for the Summer-Autumn season. The subsurface flow contribution to the sewer pipes are markedly higher than the total surface runoff volume for some events and the Summer-Autumn season. The peakiest flow rates correspond to the Winter-Spring season. Therefore, urban runoff simulation for design and management purposes should include two-way interactions between the subsurface runoff and flow in sewer pipes, and snow-influenced seasons. The developed urban P-R model is useful for better computation of runoff generated from different land cover, for assessments of stormwater management techniques (e.g. the Low Impact Development or LID) and the impacts of land cover and climate change. There are some simplifications or limitations such as the runoff routing does not involve detailed sewer hydraulics, effects of leakages from water supply systems and faulty/illegal connections from sanitary sewer are not considered, the model cannot identify actual locations of the interactions between the subsurface runoff and sewer pipes and lacks parsimony.

中文翻译：

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小型雨水集水区的高时空分辨率和综合地表和地下降水-径流建模

总结 可靠的径流估算对于城市集水区的水基础设施设计和洪水风险管理非常重要。我们开发了一个空间分布的降水径流 (PR) 模型，该模型明确表示土地覆盖信息，对城市降水水循环和流量路径的地表和地下成分进行综合建模。我们对特隆赫姆市的一个小型（21.255 公顷）雨水集水区在夏秋事件和季节以及受雪影响的冬春季节进行了参数校准和验证，分别以 5 m × 5 m 网格大小和2 分钟。校准产生了良好的性能测量（Nash-Sutcliffe 效率，NSE = 0.65–0.94）和季节性和受雪影响时期的可接受的验证 NSE。渗透过量地表径流主导着峰值流量，而地下流量对下水道管道的贡献也增加了峰值流量。根据校准期间下水道管道中模拟流量 (Qsim) 和降水 (P) 的总体积，Qsim/P 的范围从事件的 21.44% 到冬春季节的 56.50%，非常吻合与观察到的体积 (Qobs/P)。转换为集水区总模拟径流 (QT) 的降水量的最低百分比为 79.77%。蒸散量（ET）的计算表明，事件和受雪影响季节的 ET/P 小于 3%，而夏秋季节的 ET/P 约为 18%。对于某些事件和夏秋季节，对下水道管道的地下流量贡献明显高于总地表径流量。最高流速对应于冬春季节。因此，用于设计和管理目的的城市径流模拟应包括地下径流和下水道流量之间的双向相互作用，以及受雪影响的季节。开发的城市 PR 模型有助于更好地计算不同土地覆盖产生的径流，评估雨水管理技术（例如低影响开发或 LID）以及土地覆盖和气候变化的影响。有一些简化或限制，例如径流路线不涉及详细的下水道水力学，