Model data underlying the publication: Drought mitigation as a driver of flood risk: Assessing the trade-offs induced by Natural Water Retention Measures

The aim of this study is understand the effects of Natural Water Retention Measures (NWRM) on flood risk in shallow groundwater environments. These were assessed by simulating design storm events in the Chaamse beken catchment, North Brabant, The Netherlands using a sequentially coupled subssurface-subsurface modeling approach. It consists of a dynamically coupled groundwater component (MODFLOW6 model) and a component representing the unsaturated zones (MetaSWAP), which provides input to a hydrodynamic surface water model (Delft3D 1D2D FM). The MODFLOW-MetaSWAP model is based on the regional groundwater model of North Brabant, provided by the Brabantse Delta Water Authority, and was refined from the original 250x250m to a 25x25m grid. The surface water model consists of a Delft3D 1D2D FM hydrodynamic model that consists of a 1D waterway network (including drainage ditches) coupled dynamically to a 2D catchment grid of 25x25m resolution. The stream network was generated based on the Dutch database for surface water systems HyDAMO (NHI, 2024) and the drainage ditches were added manually based on the drainage network of North Brabant. Both datasets were provided by the Brabantse Delta Water Authority. The 2D grid was generated based on the Dutch national Digital Terrain Model (AHN, 2024). The outputs are gridded groundwater levels and fluxes (IDF, HED, and CBC files) from the subsurface flow model, and gridded water depth, volume and flow velocity (NetCDF files) from the surface water model, and are provided in this dataset. These include a) the long-term mean high (MHG) and mean low (MLG) groundwater levels of the long-term simulation of the baseline period (1996-2004), as well as a reference case and a drought mitigation scenario under a future climate scenario WH2050 (van den Hurk et al., 2014), b) the annual high (HG3) and low (LG3) groundwater levels used to calculate the long-term means, c) the groundwater levels of a specified day representative of the long-term simulation representative of MHG (January 2002), d) the groundwater fluxes to the surface level and stream network, e) the gridded final simulation time step outputs at point locations and maxima for water depth and volume from the surface water model. The model configuration files, as well as output files exceeding 5GB, including hourly gridded groundwater heads and surface water outputs of the rainfall events, can be provided by the authors upon request.

本研究旨在探明天然保水措施（Natural Water Retention Measures, NWRM）对浅层地下水环境中洪水风险的影响。本研究以荷兰北布拉班特省的Chaamse beken流域为研究区域，采用顺序耦合地下建模方法，通过模拟设计暴雨事件开展相关评估。该建模框架包含动态耦合的地下水模块（MODFLOW6模型）与非饱和带模块（MetaSWAP），其中非饱和带模块可为水动力地表水模型（Delft3D 1D2D FM）提供输入数据。MODFLOW-MetaSWAP模型以布拉班特三角洲水务局（Brabantse Delta Water Authority）提供的北布拉班特省区域地下水模型为基础，将原250米×250米的网格精度细化至25米×25米。地表水模型采用Delft3D 1D2D FM水动力模型，该模型将一维河道网络（含排水沟渠）与分辨率为25米×25米的二维流域网格进行动态耦合。河道网络基于荷兰地表水系统数据库HyDAMO（NHI, 2024）生成，排水沟渠则依据北布拉班特省的排水网络手动补充，两类数据集均由布拉班特三角洲水务局提供。二维网格基于荷兰国家数字地形模型（AHN, 2024）生成。本数据集包含地下水流模型输出的网格化地下水位与通量数据（存储为IDF、HED及CBC文件），以及地表水模型输出的网格化水深、水量与流速数据（存储为NetCDF文件）。具体数据包括：a) 基准期（1996-2004年）长期模拟得到的长期平均高地下水位（MHG）与平均低地下水位（MLG），以及未来气候情景WH2050下的参考情景与抗旱情景结果（van den Hurk等, 2014）；b) 用于计算长期平均值的年最高地下水位（HG3）与年最低地下水位（LG3）；c) 代表长期模拟中对应MHG的典型日期（2002年1月）的地下水位数据；d) 补给地表与河道网络的地下水通量数据；e) 地表水模型输出的网格化最终模拟时间步长点位数据，以及水深与水量的最大值数据。若有需求，作者可提供模型配置文件，以及体积超过5GB的输出文件，其中包含逐小时网格化地下水位数据与各降雨事件的地表水模拟输出结果。