CDSS Spatial Datasets for Colorado Water Districts and Divisions

About

The Open Water Foundation (OWF) developed a tool using open source QGIS software that splits Colorado’s Decision Support Systems (CDSS) spatial data layers to provide datasets for specific basins. The resulting smaller datasets, provided in useful formats, are easier to work with and benefit the Colorado water community.

The original CDSS spatial water datasets are available via the following link: CDSS Geographic Information System Data . The CDSS data is either grouped by state or water division and is available in shapefile or file geodatabase format.

The OWF tool downloads the CDSS spatial datasets and splits each original dataset to ensure that state, water division and water district datasets are available. The datasets are then exported as zipped shapefile and GeoJSON files.

This site provides access to all of the output spatial products created by the OWF tool. For more information about how to navigate this site, refer to the ‘Documentation’ tab.

Website Version: 1.0.5 (2018-06-27)

How to Use this Site

This site has not been optimized for mobile devices.

1. Select the spatial extent type.

You can view and download data for state, water division, or water district extent. Select the desired extent from choices under “Start by selecting an extent of interest:”

2. Select the water district or water division of interest.

The state extent will default to Colorado. If the selected extent type is Water Division, select the desired Colorado Water Division (1 - 7). If the selected extent type is Water District, select the desired Colorado Water District (there are a total of 78).

3. All available datasets for the desired extent will be listed in the table.

Each row of the table represents a different spatial dataset that is available to view or download. To download a dataset, click on the link for the desired spatial format. The shapefile format is packaged as a zip file because a shapefile is comprised of multiple related files. Use the View button to view the layer in a simple map. Large datasets such as statewide extent may display slowly.

Split Methods

Different methods were used to split the CDSS spatial datasets to the water district and water division extents, depending on the layer type and potential use of the data in analysis. The method performed on each dataset is included in the data table under the “Split Method” column. Note that there is not a "Split Method" column in the 'State' data table because the original CDSS data layers were published in the 'State of Colorado' extent. All three methods are explained in detail below. In the future, multiple variations of products may be created using multiple methods if feedback is received requesting such products.

(1) Select By Location (Intersect): The QGIS Select by location tool was used to split the CDSS dataset to the water district/division boundary. Any feature in the data layer that completely or partially falls within the boundary layer (water division or district) is included in the result. This method was applied primarily to point layers.

(2) Clip: The QGIS Clip tool was used to split the CDSS dataset to the water district/division boundary. As documented in QGIS, “This algorithm clips a vector layer using the polygons of an additional polygons layer. Only the parts of the features in the input layer that falls within the polygons of the clipping layer will be added to the resulting layer. The attributes of the features are not modified, although properties such as area or length of the features will be modified by the clipping operation. If such properties are stored as attributes, those attributes will have to be manually updated.” This method was generally used for line layers (e.g., streams) and polygons (e.g., irrigated lands), in which case the length and area attributes were recalculated for the clipped results.

(3) Select By Attribute: The features of the input layer are split by the unique values of the layer’s chosen attribute field. This process was not implemented via a QGIS tool but was instead implemented with Python code.

For the Water Division Boundary Layer, the original CDSS dataset (DIV3CO.shp) was split by its attribute field ‘DIV’. For the Water District Boundary Layer (at the water district extent), the original CDSS dataset (Water_Districts.shp) was split by its attribute field ‘DISTRICT’. For the Water District Boundary Layer (at the water division extent), the original CDSS dataset (Water_Districts.shp) was split by its attribute field ‘DIVISION’. Layers that included corresponding division or district attributes were split by matching the appropriate attribute value.