Selected catchment boundaries and their SILO cell percentages for AWRA modelling for the Gloucester subregion

## **Abstract** \n\nThe dataset was derived by the Bioregional Assessment Programme from multiple source datasets. The source datasets are identified in the Lineage field in this metadata statement. The processes undertaken to produce this derived dataset are described in the History field in this metadata statement.\n\n\n\nThis dataset includes files for catchment boundaries and SILO cell percentages.\n\n\n\nThe catchment boundaries were delineated using 1 sec Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) dataset with gauge locations as pour points. Catchments were then intersected with SILO climate cells for use in gridded AWRA hydrological modelling. The new boundaries are better then those delineated using the Bureau of Meteorology's (BOM) Geofabric for all catchments, except for the catchment 209003 where a flaw in the SRTM derived flowpath excluded a valley when compared with the Geofabric. This catchment was manually edited to conform with the Geofabric representation of 209003.\n\n\n\nThe grid cell percentage was calculated for all 5km resolution SILO grid cells located within each catchment. The percentage information is used for gridded AWRA hydrological modelling and for weighting average for estimating streamflow aggregated at each gauge outlet.\n\n## **Purpose** \n\nThis dataset is intermediate, delineated using 1-sec SRTM DEM dataset, and is used for AWRA hydrological modelling.\n\n## **Dataset History** \n\nA point feature dataset was created from the gauge location spreadsheet. This was compared with SRTM 1 sec derived flow accumulation and ArcMap Basemap imagery and point features manually snapped to the SRTM flowpaths reperesenting the river names in the gauge name.\n\n\n\nContributing catchment rasters were then generated using the ArcGIS 10.1 Spatial Analyst Tool "WATERSHED with snapped gauge location pour points and the SRTM derived flow direction grid as inputs.\n\n\n\nResultant catchment rasters were then exported as shapefiles and compared with the coarser Geofabric catchments. All but one catchment conformed in extent. SRTM derived catchment for gauge 209003 excluded a large flat valley (when compared to with the geogfabric due to a misdirected flowpath. This was manually corrected.\n\n\n\nCatchment shapefiles were then intersected with BILO Climate model cells to obtain 1) percentage of cell in the catchment and 2) proportion of catchment made up by the cell. Both these determinations were based on intersected areas calculated on the Albers equal area projection.\n\n\n\nThese cell to catchments ratios were then exported to database file (dbf).\n\n## **Dataset Citation** \n\nBioregional Assessment Programme (2014) Selected catchment boundaries and their SILO cell percentages for AWRA modelling for the Gloucester subregion. Bioregional Assessment Derived Dataset. Viewed 18 July 2018, http://data.bioregionalassessments.gov.au/dataset/38f3a272-66cc-4fe2-bef9-ff4aedf6fc24.\n\n## **Dataset Ancestors** \n\n* **Derived From** [GLO SW Model Calibration Gauges v01](https://data.gov.au/data/dataset/0336445d-a34c-4a4c-a83d-000a3ed1895d)\n\n* **Derived From** [Gloucester Surface Water Discharge & Quality extract v1 060314](https://data.gov.au/data/dataset/5915baad-51c9-4637-9461-88e88426a981)\n\n* **Derived From** [Geofabric Surface Catchments - V2.1](https://data.gov.au/data/dataset/ea1b6f6c-e8a3-4c78-a463-044c89857fc0)\n\n* **Derived From** [BA SYD 1 sec SRTM (h) DEM and hydrological derivatives](https://data.gov.au/data/dataset/90f5ef3c-2141-4450-b44c-1afbd843236f)\n\n* **Derived From** [Mean Annual Climate Data of Australia 1981 to 2012](https://data.gov.au/data/dataset/02418c67-f8bb-48a8-88a3-2a5c6b485f78)\n\n* **Derived From** [Geoscience Australia, 1 second SRTM Digital Elevation Model (DEM)](https://data.gov.au/data/dataset/9a9284b6-eb45-4a13-97d0-91bf25f1187b)\n\n* **Derived From** [BILO Gridded Climate Data: Daily Climate Data for each year from 1900 to 2012](https://data.gov.au/data/dataset/7aaf0621-a0e5-4b01-9333-53ebcb1f1c14)\n\n* **Derived From** [Climate model 0.05x0.05 cells and cell centroids](https://data.gov.au/data/dataset/3df5188b-f027-4d51-99a8-45e2800f29c8)\n\n

## **摘要**

本数据集由生物区域评估计划（Bioregional Assessment Programme）基于多源数据集衍生而来。源数据集的相关信息已在本次元数据声明的谱系字段中列明，该衍生数据集的制作流程则记载于本次元数据声明的历史字段中。

本数据集包含流域边界文件与SILO网格单元（SILO）占比文件。

流域边界以1秒分辨率航天飞机雷达地形测绘任务数字高程模型（Shuttle Radar Topography Mission Digital Elevation Model, SRTM DEM）数据集为基础，以监测站位置作为汇点进行划定。随后将流域与SILO气候网格进行相交运算，以用于网格化AWRA水文模拟。除编号209003的流域外，新划定的流域边界均优于采用澳大利亚气象局（Bureau of Meteorology, BOM）地理网格（Geofabric）所划定的边界。编号209003的流域存在SRTM衍生水流路径的缺陷，相较于地理网格，该缺陷导致一处山谷未被纳入流域范围，因此对该流域进行了手动编辑，使其符合地理网格对209003号流域的表征。

针对每个流域内所有分辨率为5km的SILO网格单元，计算其在流域内的占比。该占比信息可用于网格化AWRA水文模拟，以及用于计算各监测站出口处聚合径流量的加权平均值。

## **用途**

本数据集为中间产物，基于1秒分辨率SRTM DEM数据集划定，用于AWRA水文模拟。

## **数据集历史**

首先从监测站位置电子表格中创建点要素数据集，将其与SRTM 1秒分辨率衍生的流量累积数据、ArcMap底图影像进行比对，并将点要素手动对齐至与监测站名称中河流名称对应的SRTM水流路径。

随后以匹配后的监测站汇点与SRTM衍生流向栅格为输入参数，通过ArcGIS 10.1空间分析工具中的“流域（WATERSHED）”工具生成贡献流域栅格。

将生成的流域栅格导出为形状文件（shapefile），并与分辨率更低的地理网格（Geofabric）流域进行比对。除一处流域外，其余所有流域的范围均与地理网格流域相符。编号209003监测站对应的SRTM衍生流域因水流路径导向错误，遗漏了一处大型平缓山谷（相较于地理网格流域），因此对其进行了手动修正。

随后将流域形状文件与SILO气候模型网格单元进行相交运算，以获取两个参数：1）网格单元在流域内的占比；2）该网格单元在流域中所占的面积比例。两项参数的计算均基于阿尔伯斯等面积投影下的相交面积。

随后将上述网格单元与流域的占比数据导出至数据库文件（dbf）中。

## **数据集引用**

生物区域评估计划（2014）《格洛斯特次区域用于AWRA模拟的选定流域边界及其SILO网格单元占比》，生物区域评估衍生数据集。2018年7月18日查阅，http://data.bioregionalassessments.gov.au/dataset/38f3a272-66cc-4fe2-bef9-ff4aedf6fc24。

## **数据集上游来源**

* **衍生自** [GLO SW模型校准监测站v01](https://data.gov.au/data/dataset/0336445d-a34c-4a4c-a83d-000a3ed1895d)

* **衍生自** [格洛斯特地表水流量与水质提取物v1 060314](https://data.gov.au/data/dataset/5915baad-51c9-4637-9461-88e88426a981)

* **衍生自** [地理网格表面流域-V2.1（Geofabric Surface Catchments - V2.1）](https://data.gov.au/data/dataset/ea1b6f6c-e8a3-4c78-a463-044c89857fc0)

* **衍生自** [BA SYD 1秒SRTM（h）DEM及水文衍生数据](https://data.gov.au/data/dataset/90f5ef3c-2141-4450-b44c-1afbd843236f)

* **衍生自** [澳大利亚1981-2012年平均气候数据](https://data.gov.au/data/dataset/02418c67-f8bb-48a8-88a3-2a5c6b485f78)

* **衍生自** [澳大利亚地球科学局1秒SRTM数字高程模型（DEM）](https://data.gov.au/data/dataset/9a9284b6-eb45-4a13-97d0-91bf25f1187b)

* **衍生自** [SILO逐日气候数据（1900-2012年）](https://data.gov.au/data/dataset/7aaf0621-a0e5-4b01-9333-53ebcb1f1c14)

* **衍生自** [0.05×0.05分辨率气候模型网格单元及质心](https://data.gov.au/data/dataset/3df5188b-f027-4d51-99a8-45e2800f29c8)