A consulting engineer firm has delivered the results of an area groundwater resource analysis for a second area of Delta County.
The Phase II report deals with the "North Fork Valley Area and Associated Terraces" (i.e. mesas)
The study follows on the Phase I study which dealt with Oak Mesa and which was completed in 2012.
The studies, which cost the county $15,000 each, provide conceptual models of "hydrologic and geologic subsystems" that underlie county landscapes. The studies attempt to describe and map the hydrologic and geologic features that affect groundwater flows and aquifer recharge systems in defined areas.
One key feature of the Phase II report as presented to the county commissioners in November was the system of shallow aquifers in the North Fork. The aquifers are supplied by irrigation water that "leaks" from ditches and filters through sands and gravel to re-emerge above ground as springs.
The study authors noted that projects to put irrigation water into pipes or other devices that isolate it from ground contact could affect some adjudicated water sources, including springs, that are dependent on irrigation ditch leakage for their supply.
The county environmental health department told the DCI that some domestic water companies in the North Fork Valley take their raw water supplies from springs that have appeared only since the advent of irrigated agriculture in the county.
The study authors also noted that the area included in the Phase II analysis is comprised of geologic and hydrologic features that are completely different from the nearby Oak Mesa area that was analyzed in the Phase I report.
Information in the studies is of interest to the county environmental health department and the planning department. Information would also be of interest to water users including ditch companies, domestic water suppliers and ag producers.
The studies and the information in them is public but they have not yet been made available via online mapping, though a project to do so is underway.
Responding to an email request on Nov. 26, the county GIS department stated, "Because these studies contain a lot of data (it can't be added) to the existing online map — it would make the map way too confusing and significantly add to the download time. (We are) working on producing a new map to post in addition to our existing map. (We) don't have an exact timetable yet. (We are) aiming for the first quarter of 2014."
The two engineers who are consulting with Delta County on the project also completed a decade-long study of the topic for Pitkin County. Pitkin County has made some of the information in its study series available to the public online, and it also sells some information sets from it to interested parties.
Results of the Pitkin County study (called HESA, for hydrologic and environmental systems analysis) can be found by anyone interested at the Aspen/Pitkin website by navigating through the following series of tabs and topics: county department; community development; environmental health; water resources.
A third study in the Delta County series is planned, the health department said, but the area to be analyzed hasn't been determined yet.blog comments powered by Disqus