Apple Gate

Riverside Reservoir, Photo by Richard Stenzel
Riverside Reservoir, Photo by Richard Stenzel

Gravel Pit Reservoirs

We have substantial experience with converting existing gravel pits into lined raw water storage reservoirs. This includes design of clay liners, slurry walls, inlet and outlet pipes, pump stations, interconnects, and side channel spillways. We are also experienced in technical revisions, amendments and permitting through the Division of Minerals and Geology for gravel mining and modifications such as conversion of sites from ground water storage to lined reservoir storage. We have also performed site planning, permitting, and engineering design for mining operations and reclamation activities, including permitting services at Federal, State, and local levels.

Specific Project Experience

Tigers Reservoir—Design and Reclamation

Applegate Group, Inc. was hired by Aggregate Industries to increase storage volume in an approved lined gravel pit reservoir. The location of the reservoir site is within the floodway of the South Platte River. The reservoir will store 2,640 ac-ft of water and will have a maximum embankment height of 8 ft above existing grade. The project involves putting a partial ring dike around the gravel pit to create a level crest, however, the addition of this ring dike made the structure jurisdictional according to the state engineers rules and regulations. In addition, the reservoir lies entirely in the 100-year floodplain and the floodway. Federal Emergency Management Agency (FEMA) requirements do not allow for any rise in the floodway along this section of the South Platte River.  Through several iterations in the HEC-RAS model and meetings with FEMA and Urban Drainage and Flood Control District, the spillway and embankment was raised so as not to cause a rise in the water surface elevation outside of the owners property.

Fulton Lakes

Fulton LakesApplegate Group was retained by Aggregate Industries to evaluate lining alternates for a gravel operation at the Cooley Reservoir & Fulton Wildlife Area in the north Denver metro area. Initial work involved geotechnical analysis and slope stability studies to determine stable bank configurations and to propose construction standards. The pit was mined in three cells with a total storage capacity of approximately 5,200 ac-ft. A  liner using clay shale for the impermeable core was selected for the method of lining. Applegate Group produced a full set of Construction Plans and Specifications for the project. Applegate Group worked to meet all of the design requirements and concerns raised by the various interested parties. The site is located in the South Platte River floodplain and floodway. Applegate Group provided third party quality control and construction assistance throughout the construction process.

City of Greeley—Gravel Lakes Storage Study

This study pertained to the viability of using gravel pit storage on the lower Cache la Poudre River for non-potable uses for the City of Greeley. Lined gravel pits are an effective water supply alternative due to the low environmental impacts and generally very little public and/or Federal concerns. Our work for this project included evaluations of possible uses of lined gravel pit storage, site evaluation by river reach, sources of water for filling, gravel pit liner design and construction methods, firm yield increase of the water rights, partnering opportunities, and groundwater recharge possibilities.