Products

RIO GRANDE DECISION SUPPORT SYSTEM

State of Colorado Division of Water Resources/Colorado Water Conservation Board

Agro Engineering, Inc., acting as a subcontractor to Leonard Rice Consulting Water Engineers, was selected by the State of Colorado Division of Water Resources and the Colorado Water Conservation Board to perform the Irrigated Lands Assessment of the Rio Grande Basin of Colorado as an integral part of the Rio Grande Decision Support System. The purpose of the irrigated lands assessment was to determine the extent (i.e. ditch service area boundary and irrigated parcel boundary), and character (i.e. crop type) of irrigated lands in the Rio Grande Basin. The character (i.e. land cover class) of non-irrigated lands within the ground water model area was also determined.

Four GIS products were developed as part of the RGDSS irrigated lands assessment:

• A Ditch service area theme was produced to delineate the service area boundaries of the surface water structures in the basin.

• A composite false-color satellite image was developed to serve as a backdrop to other GIS themes.

• An irrigated parcel theme was developed to delineate the boundary and important attributes of the irrigated parcels within the basin.

• A land cover classification theme delineating irrigated and non-irrigated land types was developed to assist in determining the consumptive use of the non-irrigated portions of the basin.

The project involved preparing a detailed GIS inventory of all ditch service areas within the basin. Interviews were conducted with numerous water users and public meetings were held to delineate ditch system service boundaries. Satellite imagery was processed and composited to serve as a baseline. The satellite imagery was also used to create a land cover classification providing an indication of the crop type grown on the irrigated lands and the land cover class associated with non-irrigated lands. All irrigated parcels in the basin were then digitized from the satellite imagery to create a GIS data set of irrigated lands. The irrigated parcel theme is used by the consumptive use model and surface water model of RGDSS to allocate water to specific lands. A land cover classification theme was developed to indicate the land cover class of both irrigated and non-irrigated lands within the ground water model area of the San Luis Valley floor. This theme, which recognized nine non-irrigated land cover classes and five irrigated land crop types, was used to determine consumptive use for the ground water model of RGDSS.

The project was coordinated with a Technical Advisory Committee comprised of representatives from local, state and federal agencies and private landowners. Numerous public meetings were held to gather study input and present study conclusion.