Projects



Water Resources Services
Polaris Group's water resources projects cover a broad range of service areas. These projects range from small studies for a private landowner to large regional studies for the Federal Government. Examples of recent water resources projects include:

Hydrologic Study
Devils lake, North Dakota


Project Tasks

  • GIS analysis and classification of depressions and watershed data
  • Hydrologic modeling of depression storage in the watershed
  • Evaluate effect of depression storage on Lake levels
  • Assess alternatives to reduce future flooding

Project Description

Devils Lake is a landlocked lake in northeastern North Dakota. Since 1993, this lake has nearly quadrupled in size to approximately 120,000 acres and increased in elevation over 20 feet. The expansion of the lake has inundated farmland and hundreds of roads and forced 350 homes to be moved.

Polaris Group teamed with WEST Consultants to evaluate the significance of depression storage within the Devils Lake watershed. This work was part of a contract with the U.S. Army Corps of Engineers. This evaluation involved using GIS to delineate watersheds and classify over 30,000 depressions based on DEMs, USBR photos, NWI maps, and soils survey maps. The depressions were modeled using HEC-HMS and the model was calibrated to lake levels and gaging station data.

The model was used to estimate lake levels for selected future meteorological scenarios. Lake levels were estimated for several flood reduction alternatives including varying degrees of restoration of drained depressions. An evaluation of precipitation records and discharge gages in the basin and a sensitivity analysis of runoff to snow pack water equivalent was also performed.

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Regional Stormwater Management Facilities
Polaris Group staff has analyzed and designed over 50 stormwater management facilities in the past 5 years. These facilities have ranged from small ponds to large regional facilities. Our analysis and design of these systems considers the setting and factors that will affect their performance. These designs are often part of recreational and stream corridors that incorporate wetland and upland prairie features.

Regional Pond Along Creek


Project Tasks

  • Hydrologic modeling of the local and regional watershed
  • Analysis of pond effects on receiving creek
  • Hydraulic modeling and design of storm sewers and staged outlet
  • Water quality and flood control basin design
  • Floodplain modifications and FEMA permitting

Project Description

The hydrologic analysis included modeling the 17,000-acre regional watershed in order to accurately estimate tailwater elevations on the pond outlet structures, inflows from the Creek into the basin, and the effect of the pond on the creek.

This regional pond was located within an abandoned irrigation water/sewage holding pond to minimize wetland and floodplain impacts. The regulatory floodway and floodplain for this area needed to be revised to accommodate the pond, a nearby development, and the storm sewer system for the area. A two cell pond was designed to allow easy maintenance and optimal water quality treatment.

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Regional Flood Storage to Replace Dam


Project Tasks

  • Hydrologic and Hydraulic modeling
  • Evaluate alternatives to replace an NRCS dam
  • Prepare and evaluate flood storage and wetland banking alternatives
  • Design roadway and creek crossings, grade stabilization structures, ponds, and wetland bank
  • Prepare grading and development plan for soccer/recreational park and residential developments

Project Description

Spring Creek flows through the City of Northfield and drains approximately 6,500 acres. Rain storms during 1993 and 1998 resulted in flooding of homes, erosion in a golf course, damage to roadways, and damage to an NRCS dam. The damage to the dam further increased the potential for flooding and produced steeper channel sections that were subject to erosion.

Polaris Group designed a regional stormwater system to replace the flood storage provided by the dam. The pond also served as a wetland banking area and incorporated creek crossings and riffle sections.

An 80-acre park and recreational facility was also designed. The facility has soccer fields, softball fields, play area, ponds, natural/prairie areas, and trails. Polaris Group developed the site grading plan, investigated soils, and design storm dranage systems.

The final system is an important part of the City’s natural corridor and recreational trail.

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Industrial Park Adjacent to Special Water


Project Tasks

  • Hydrologic and Hydraulic modeling
  • Design trunk storm sewer and flood control system
  • Design water quality pond and infiltration area
  • Assess interaction with adjacent river
  • Prepare plans and specifications
  • Project permitting

Project Description

A 40-acre industrial park is proposed along the Cannon River. The Cannon River has been designated a State Special Water and has a TMDL for turbidity impairment. This industrial park and an adjacent 300 acres of developed area will discharge to the River and its adjacent floodplain. Because of site constraints and land ownership issues, the pond needed to be located within the river floodplain.

Polaris Group was hired by the City to develop the regional system to convey stormwater through the industrial park, to provide flood control, and to meet water quality strict discharge requirements. Because of the large drainage area, the system was economically designed by using an overflow basin to separate larger flood flows from the low flows that needed to be treated.

The pond design was challenging because of its location within the river floodplain. Special measures were designed to make the pond as functional as possible when the River flooded. An adjacent infiltration area was used to meet volume control requirements. The pond layout was made to look natural and incorporate both wetland and open water features. The vegetation plan enhanced the natural looking design and complemented the adjacent floodplain.

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Water Balance Studies
Reservoir Water Balance Study
Proposed Power Plant


Project Tasks

  • Investigate water supply options for a proposed power plant
  • Water balance study of 3 reservoirs as potential water supply sources
  • Perform water balance study of local watershed and proposed storage basin

Project Description

A proposed power plant needed water for cooling. Groundwater was not a feasible source because of its quality and depth.

Polaris Group investigated surface sources of water for meeting the plant's needs. Hydrologic and water balance evaluations were performed for 3 nearby reservoirs and the local watershed to determine the amount of water that would be available. The model predicted runoff, evaporation, infiltration, and discharge at each location. The model was calibrated to reservoir levels at one of the reservoirs. Various future meteorological scenarios were considered to evaluate management alternatives and statistically assess dry periods.

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Water Balance Study
Proposed Commercial Site


Project Tasks

  • Water balance modeling of infiltration basin
  • Estimate discharges to a trout stream and the assess temperature of discharge water

Project Description

A proposed development was closely scrutinized because of its potential impact on the adjacent trout stream. Polaris Group prepared a water balance model that determined daily precipitation, evaporation, infiltration, snow storage, basin storage, and discharge. This model considered 50 years of historic data in assessing impacts to the trout stream for several stormwater management scenarios.

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Water Balance Study
Expert Witness Case in Michigan


Project Tasks

  • Prepared a water balance model to simulate lake level changes over a period of 25 years using a daily time step
  • Included evaporation losses, seepage losses and inflows, daily rainfall and runoff inputs, and culvert outflows

Project Description

A developer adjacent to a lake in a Detroit, MI suburb sued a road construction contractor for flooding developable lakeshore property and creating wetland conditions.

Polaris Group prepared a water balance model for the court case and worked with the legal team to defend the contractor with the model results. The defense was successful. The judge found no fault with the contractor.

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Low Impact Development Practices
Numerous Sites


Project Tasks

  • Selection and design of infiltration system
  • Evaluation of system
  • Field monitoring
  • Prepare plans and specifications
  • Project permitting

Project Description

Polaris Group has been involved in the selection, design, and implementation of numerous practices that encourage infiltration and reduce the runoff from developed sites. These designs have included measures to meet requirements for no increase in the runoff volume, retrofits to existing sites, and measures to allow the development to better fit the site conditions.

Our efforts have included field studies. Systems that we have evaluated and designed include: infiltration areas, rainwater gardens, permeable pavers, underground storage systems, netlawn, mitsack storm sac and ECS.

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Stream Gaging
Gate and Turbine Calibration


Project Tasks

  • Developed stage discharge relationships for several streams
  • Calibrated and verified discharge rating curves for the gates and turbines for several dams and hydroelectric facilities

Project Description

As a part of a Federal Energy Regulatory Commission (FERC) re-licensing process, Polaris Group established rating curves (elevation vs discharge) for numerous stream gaging locations. These gaging stations were installed to monitor flows into and from reservoirs. The rating curves required flow measurements for a range of discharges. Standard U.S. Geological Survey methods were typically used.

Polaris Group streamlined the process in a few ways. Gaging trips were coordinated between several sites to minimize field time. Where possible, a range of measurements were made at one time by regulating the flow upstream with the reservoir gates. At other locations, a weir was placed in the flow which initially blocked the discharge. Measurements were taken just after the flow started over the weir and proceeded until after the flow reached a stable level. This provided a continuous record of flows from zero to the level of flow in the streamon that day.

The FERC re-licensing process also required verification of the gate and turbine discharge curves at hydroelectric facilities. Often the flow configurations made measurements difficult. Polaris Group calibrated ten different facilities using several different methods ranging fromstandard USGS in-stream flow measurements to acoustic doppler current profiling. Where possible, gate calibration efforts were coordinated with downstream gaging station measurements to complete two project requirements at one time.

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Stream Geomorphology
Site Remediation Project


Project Tasks

  • Hydrologic and hydraulic modeling
  • Evaluate the various creek relocation options on flood levels and velocities
  • Design rock weir for grade control
  • Design erosion control features and bioengineered bank stabilization
  • Design tidal wetland mitigation
  • State, local and federal permitting
  • Prepare plans and specifications

Project Description

Keens Creek flows adjacent to a former wood treating facility near Salisbury, Maryland and discharges into the Wicomico River. Contaminates from the wood treating process were identified along the west bank of the creek near its outlet. Creek relocation was required to facilitate containment of the contaminates within a subsurface barrier wall. An objective of the design was to move the creek without affecting the creek’s natural flow characteristics. This was achieved by creating a new channel east of the existing alignment that conveys the same amount of water with similar water surface elevations and at similar flow velocities. The design was complicated by the three-foot tidal fluctuations at the site and a wood bulkhead constriction at the outlet of the creek.

Several design alternatives were evaluated using hydrologic and hydraulic modeling. The final design used a rock weir near the outlet to match pre-project flow characteristics. The new streambanks and floodplain areas were protected using bioengineering techniques and native tidal wetland plants. Polaris Group also prepared plans and specifications for the project.

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