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Street and Utility Improvements

June 3, 2024

Poor drainage was causing accelerated deterioration along Hawarden’s Avenue L, which serves as the primary collector route to the town’s nursing facilities and the local hospital. When repeat efforts to patch and repair this critical stretch of roadway were only fleetingly effective, the City of Hawarden partnered with DGR Engineering to develop a comprehensive approach for improving Avenue L for the long-term benefit of the community.

The improvements included installing a new storm sewer system, making repairs to the existing water main and sanitary sewer, and taking steps to improve future drainage, all before installing new 6” concrete pavement.

Rock Riffle Dam

June 3, 2024

Witnessing the sharp decline in Regional’s wellfield capacity during 2020 and 2021, Regional and DGR Engineering (DGR) began conversations in 2021 with the intent of shoring up Regional’s wellfield capacity.

The principle behind a riffle dam structure is that the water in the river channel and water in the adjacent aquifer are hydraulically connected. Raising the level of the river raises the water level in the aquifer, giving wells more available drawdown to pump more water. The correlation between the river and the aquifer levels is dependent on the geologic conditions of the aquifer. DGR helped Regional secure the services of LRE Water, a hydrogeology firm which used previously-collected geologic records to set up a model, which confirmed that the aquifer and the river had a strong hydraulic connection.

Obtaining permits from the DNR to build the riffle dam required significant effort. Notably, the river programs and fisheries divisions were concerned respectively about impedance to recreational paddlecraft and fish passage. It was important that the structure was designed with a deep, center channel to allow navigation of the river. DGR used HEC-RAS river modeling to simulate multiple iterations of dam heights to determine the maximum height that could be used. Through the modeling and permitting process, a structure height was settled on to raise the upstream river level 2.83 feet.

The structure has netted Regional an approximately 100 GPM in additional wellfield capacity. This may not seem like much, but it makes a big difference in helping Regional meet its customers’ water needs. Perhaps more importantly, it helped stop the drought-induced aquifer decline and it buys Regional time as they and DGR pursue additional water supply solutions.

Neighborhood Revitalization

April 12, 2024

Neighborhood Revitalization

Paved Asphalt Street

Neighborhood Revitalization

Infrastructure Replacement in Dell Rapids

Project Owner:
City of Dell Rapids, SD

Unique Project Challenges:

  • Phasing of construction to minimize disturbance to residents in project area
  • Coordination and communication with 200-plus residents, property owners, and business owners impacted
  • Removal of over 3,000 cubic yards of quartzite bedrock for utility replacement, which often
    required blasting
  • Relocating the water mains that were in the alleys, which involved directional drilling of service lines and backyard connections
  • Replacement of a large box culvert originally built from quartzite rock, which involved both precast and cast-in-place concrete
  • New ADA-compliant sidewalks and curb ramps throughout the project, including many areas that did not have sidewalks before
  • Improving the drainage through the project area while matching into existing driveways, which required extensive design effort

Key Features:

  • Nearly 30 city blocks of total infrastructure replacement throughout residential neighborhood
  • Replacement of existing sanitary sewer, water, and storm sewer utilities at four railroad crossings
  • Two construction contracts, combined total cost of more than $8.5 million
  • Funding for the project included:
    - $600,000 SDDOT Community   Access Grant
    - Grants and loans through SRF
      programs
    - City of Dell Rapids local funds
civil collage
Storm Sewer Near Box Culvert
culvert replacement collage
Concrete Paving 2
sfo quote

Replacement of deteriorating infrastructure has been a high priority for the City of Dell Rapids for many years, and in 2016 the City decided to take on a neighborhood reconstruction project that would be their largest yet. When it came to determining the area of town that needed the improvements the most, it did not take long for the answer to become clear. In the years prior, the City Public Works department had spent considerable time fixing water main breaks and sanitary sewer issues in an older neighborhood located in the southeast quadrant of town. DGR Engineering (DGR) assisted the City with their annual capital improvement planning process, which helped to identify the scope of the nearly 30 city block reconstruction project that would ultimately be referred to as the Southeast Infrastructure Improvements.

DGR worked closely with the City to develop the project design, and also provided construction administration and observation services. The project was constructed in multiple phases over a three-year period, which helped limit the impact to the residents in the area. Construction occurred under two separate contracts with the first phase commencing in 2019 and project completion occurring in 2022. The improvements included complete replacement of the sanitary sewer collection system, drinking water distribution system, storm drainage system, streets, and sidewalks within the limits of the project. The borings completed during the initial design indicated quartzite bedrock was less than 6 feet below the surface throughout much of the project area, with some areas having bedrock less than two feet below the surface. Rock blasting was needed to provide sufficient depth on the new water mains and adequate slope on the new sewer mains. More than 3,000 cubic yards of quartzite rock was excavated for the project. The rock blasting operations required greater communication than normal with the nearby residents and the natural gas company.

The project included other unique elements in addition to the rock blasting. There were over 1,800 feet of existing sanitary sewer and water mains that were installed in narrow alleys, and there was not enough space to replace and maintain both utilities in the alleys. Thus, the new water mains were installed in the street and new water services were directional drilled from the street to the backyards where the connections were made. The project also included replacement of a shallow box culvert that was built masonry style from quartzite rock. A new precast box culvert was installed across the street, which involved rock blasting followed by cast-in-place concrete transition sections on each end to tie into the existing masonry quartzite rock drainage channel.

New ADA-compliant sidewalks and curb ramps were installed throughout the project to improve pedestrian travel. New streets were constructed with asphalt pavement in the residential areas and with concrete pavement along the truck route. All streets were constructed with concrete curb and gutter. Storm drainage in the area was greatly enhanced by improving the slopes of the streets and installing new storm drainage systems. Coordination with the local railroad entity was required for replacement of the existing sanitary sewer, water, and storm sewer utilities at four railroad crossings.

The project was financed by multiple funding sources. The City was awarded a $600,000 grant through the SDDOT’s Community Access Grant program for the improvements along the truck route. Most of the project funding was received through the State Revolving Fund (SRF) programs that are administered by the South Dakota Department of Agriculture & Natural Resources. Both grant and loan funds were received through the SRF programs. The City also contributed local funds for a portion of the project costs.
DGR and the City of Dell Rapids have formed a strong working relationship over the last 30-plus years, which was key to the success of this project. DGR and the City emphasized coordination and communication with the 200-plus residents, property owners, business owners, and others affected by the project, from initial design concepts through final completion. This coordination and communication took place in many forms, including public open houses, various mailed letters, individual meetings, bi-weekly progress meetings and newsletters throughout construction. Replacing existing infrastructure in a developed residential neighborhood is challenging for all involved, but exceptional coordination and communication again proved to limit the difficulties in the process.

The Southeast Infrastructure Improvements project was an investment by the City of Dell Rapids into one of the older neighborhoods in town. The project revitalized the neighborhood by replacing dilapidated infrastructure with new, dependable infrastructure that will serve the community for many years to come.

Infrastructure Improvements

April 8, 2024

DGR Engineering (DGR) and the Town of Chancellor worked together to plan an infrastructure improvements project. Ultimately, solutions were divided into three project phases. Phase 1 included Main Street and the west half of the community. The Town of Chancellor received funding which included nearly 89% in grants and principal loan forgiveness.

Phase 1 included the beginning of a new storm sewer system. DGR and the Town worked with landowners to acquire the needed land and easements for a new storm sewer outlet. It allowed the storm sewer to be extended across the southern end of town in each of the phases of construction, connecting each of the street’s drainage to a larger diameter storm pipe to improve drainage.
Chancellor was awarded Clean Water and Drinking Water State Revolving Funds for their planned Phase 2 project, which covered the central part of the community. They followed with funding for their Phase 3 project and were successful in securing approximately 85% grant and principal loan forgiveness for both Phase 2 and Phase 3 projects.

Each of the project phases included the replacement of sanitary sewer main and services with PVC pipe, replacement of all sanitary manholes with new concrete manholes, replacement and up-sizing of PVC pipe water main and water services as well as adding additional water services to areas that previously did not have existing water main. New street surfacing was placed after the underground improvements. While Main Street included concrete surfacing on the north two blocks, the remaining streets will maintain a rural section paved with asphalt surfacing. The rural section is designed with minor ditches graded along the roadways and culvert replacement at the driveways and intersections to allow the stormwater to flow to the storm sewer system, located at the southern portions of the streets, to reduce the stormwater ponding that had occurred.

The infrastructure investment will significantly improve and benefit the community and all residents. They are looking forward to project completion and many years ahead with reliable infrastructure to support their Town.

Water Treatment Plant

April 8, 2024

The original Great Bend Water Treatment Plant was constructed in 1983 and the equipment had outperformed its useful life. Red Rock Rural Water System (Red Rock) faced a dilemma: rehab a nearly 40-year-old facility to extend its useful life, or start fresh by constructing a new facility. Red Rock worked with DGR Engineering to begin design of a new state-of-the-art water treatment plant that would provide continued growth opportunity for Red Rock’s next 40 years of operation.

Two new production wells were drilled and developed a total of 1,100 gpm of new capacity. Red Rock also wanted to incorporate operational improvements over the old treatment plant, including a dedicated office space with a fully functional master SCADA computer that can operate all components of the plant, as well as all other facilities in the water system. Pneumatically actuated valves on the filters are tied into the SCADA controls to automate the backwash process.

Two rapid infiltration basins were constructed to collect backwash water from the filters. The infiltration basins allow the backwash water to recycle back into the aquifer while filtered particles settle out on the surface of the basin.

The new Great Bend Water Treatment Plant went into full-time operation in May 2023. By the time the new facility went on-line, the original Great Bend treatment plant was functioning at only 60% of its designed capacity. Initially the new facility will operate at 1.2 million gallons per day (MGD) at a flow rate of 1,000 gpm.

The building is expandable to add future treatment equipment that can double the treatment capacity as water demands increase in the future. With three times more water available and enough annual water appropriation to operate at full capacity all year long, the new facility has become Red Rock’s primary water source.