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Water Source Development

October 12, 2018

Red Rock Rural Water System was looking at the prospect of a costly rate increase from the City of Windom, who is one of their primary water suppliers.  In addition to meeting their own water needs and selling water to Red Rock, the City of Windom supplies water to the City of Bingham Lake and the nearby POET ethanol plant.  Windom’s water supply was on the decline and they were considering a new water source from a deeper groundwater formation that would require reverse osmosis treatment and a hefty increase in water rates.

DGR Engineering was already working with Red Rock on a constructing a new 1.2 MGD water treatment plant.  During the water source exploration phase of that project a potential source was identified in a shallow alluvial aquifer along the Des Moines River.  The only problem with the site was that it was within a mile of the County landfill, which could be a major problem from a public perception.  However, the bad optics for a drinking water source wasn’t a problem if the source was developed as an industrial water supply.

Looking for a good regional solution to Windom’s water crisis, DGR Engineering and Red Rock Rural Water System teamed up with POET to perform a program of exploratory drilling, test pumping and well field development.  DGR designed three production wells capable of supplying 1.4 MGD to the ethanol plant and 9-miles of 10” diameter raw water main to transmit the water from the source to the point of use.

Red Rock’s out-of-the-box approach to a declining water supply and their long-term relationship with DGR Engineering ended up being a win-win-win situation for everyone.  POET had a new water source with a lower cost of production while keeping Windom as a back-up supply.  POET continues to pay for the debt retirement on their original Windom water source in exchange for an emergency connection.  Red Rock avoided a rate increase on their water purchases from Windom, allowing them to continue to utilize a vital water source for their system. Windom was able to reduce their water use by 1/3 and cancelled their plans for a new RO water treatment plant, saving the residents the cost of a rate increase.  The entire project was Addition by Subtraction.

Pipeline Improvements

October 12, 2018

Osceola County Rural Water is a regional water provider whose service territory footprint covers an extensive four county area and over 1,200 square miles in Northwest Iowa. The water system’s continual growth eventually led to water use demands that could not be met by the existing distribution system. Using a calibrated hydraulic model, DGR identified numerous areas of the system needing pipeline improvements to maintain pressure. Additionally, the capacity of originally constructed transmission main had been depleted over the years.

The resulting 56-mile pipeline project was designed, permitted, bid, installed, and started up in less than two years from the project’s inception. The pipeline improvements will serve to accommodate Osceola County Rural Water’s ever growing water demands well into the future.

Search for High Capacity Wells

October 12, 2018

As the Little Sioux River winds through the O’Brien County, it passes through a narrow valley with a shallow alluviale aquifer where Osceola County Rural Water has drawn water for years.  The depths and quality of sands and gravels is highly variable throughout this valley.  OCRWS rapid growth in water demands had pushed their existing wells to the limit, and it was now time to start looking for additional water supply.

The river valley in this area is very narrow, but potential well sites were limited by the size of the floodway and land owners in the valley who were less than cooperative.  OCRWS was eventually able to secure an option to purchase on nearly 2 quarter sections of ground, but with so much land to cover, traditional exploration methods using a drilling rig would be expensive and possibly miss highly productive areas.

DGR Engineering partnered with WSP to perform 4 days of surface resistivity testing to give multiple cross section “snap shots” of the aquifer thicknesses in the area.  With field results available in the field instantaneously, we were able to quickly dismiss large sections of the exploration areas and focus on areas of high potential.  We were even able to access public access state land at the last minute to expand our search.  We were able to do this without any permits, due to the non-evasive nature of the testing.

In the end, our team located 2 new well sites in the original search area.  We were also able to identify a 70’ deep vein of gravel on State owned ground, nearly double what we found anywhere else in the search.  Physical drilling in these locations confirmed the results, and now we are in the final stages of the necessary state permits to drill two new wells on State ground, which will be the most productive wells OCRWS has in the valley.

Ground Storage Reservoir

October 12, 2018

Construction of a bolted steel glass lined tank, foundations, and miscellaneous appurtenant work.  Nominal size is 300,000 gallons, 36′ diameter, 38′ high.

The ground storage reservoir is a critical component of the water treatment process, allowing flow equalization between the filtration process and the softening system.