Projects by Discipline / Environmental Science

Mariano Exchange Ditch System Assessment

 Hydrosphere was retained by the Big Thompson Watershed Forum, in cooperation with the City of Loveland and the Consolidated Home Supply Ditch and Reservoir Company, to evaluate sources of turbidity in the Mariano Exchange Ditch (MED).

The MED is an irrigation ditch that delivers water from Boedecker Reservoir to the Big Thompson River near Loveland, Colorado. Boedecker Reservoir, an off-stream reservoir, fills in the winter by diversions from the Big Thompson and delivers water back to the river via the MED in the late summer. These late summer deliveries are in exchange for water diverted from the Big Thompson further upstream for agricultural irrigation. Water discharged from the MED is characterized by high turbidity at its confluence with the Big Thompson, as seen in the photo at left.

• The objectives of the project are to:
• Analyze the turbidity and other quality characteristics of the water
• Characterize sources of turbidity and nutrients
• Suggest mitigation alternatives

During the first phase of the project in 2005, several site visits under a variety of conditions were made to the MED and the reservoir. Hydrosphere conducted a visual inspection of the entire length of the MED and in the vicinity of the reservoir outfall to assess potential point and nonpoint sources. Water quality and soil samples were collected along the MED and in the reservoir. These efforts have been focused on identifying pollution sources within Boedecker Reservoir and the MED immediately downstream of the reservoir (photo below).  Potential storm water sources from the adjacent and rapidly growing area of Loveland are also being evaluated.

Complementing these water quality analyses are parallel water rights and facilities evaluations.  Hydrosphere's engineers have been investigating potential non-structural mitigation alternatives on the lower Big Thompson, such as employing different reservoirs to store exchange water, trading water rights with other entities to eliminate the need for exchange releases, and changing land use so that late season water is not needed.

The next phase of the project will involve working closely with the Big Thompson Watershed Forum to evaluate likely mitigation measures and to develop plans for additional sampling and data collection.

Hydrosphere services employed in this project have included:

• Background data gathering
• Synthesis of existing information
• Field reconnaissance of point and non-point sources
• Water quality sampling and testing
• Soil sampling and testing
• Evaluation of data
• Water rights analysis
• Report writing