Polk approves spending $17k on Lake Adger dredging study

Published 10:00 pm Wednesday, November 12, 2014

by Leah Justice

Polk County has made its first step in dredging Lake Adger by approving a study that will not only discover the best way to dredge the lake but also find potential funding sources such as grants.

County commissioners met Nov. 3 and approved paying Altamont Environmental $17,396 to conduct the study.

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Polk County Soil and Water Director Sandra Reid volunteered her services to look at dredging options and to help find funding sources to dredge the lake. In order to seek grant options, a study is needed, Reid said.

Stu Ryman with Altamont met with commissioners and said Altamont conducted a Green River Watershed study last year and the Lake Adger dredging study would be a follow on last year’s study.

Ryman said Isothermal Planning and Development Commission (IPDC) received a grant to conduct the watershed study, which looked at potential sources of sediment and other pollution in the watershed. The study also looked at all tributaries in the watershed area to Henderson County.

Altamont’s proposal for the dredging study includes identifying potential methods to dredge the lake, determining any permits required and to work with various contractors to come up with cost estimates.

Ryman said he thinks the study will help commissioners decide when dredging should be done, identify when the costs need to occur and support grants.

The study will map the area of sedimentation in Lake Adger and the Green River upstream of the lake, perform a bathymetry study (the study of beds and floors of bodies of water), estimate the volume of sediment, determine permitting and dredging methods, evaluate the potential beneficial reuse of sediment, prepare a preliminary cost estimate for dredging and handling and identify potential funding sources.

Altamont will prepare a report and present it to commissioners once the study is complete.

The study will include taking 10 samples of sediment with more possible if necessary.

Reid said some of the urgency for getting a study done is a couple of dams that will be disassembled in Henderson County soon. Lake Adger will likely be getting sedimentation from the disassembly of the dams.

Commissioner chair Ted Owens asked if minimizing future sedimentation will be a part of the study.

Ryman said yes and also best practices for construction and stabilizing stream banks. Ryman said one of the other things the study will look at is whether or not it makes sense for the county to do routine dredging or if dredging now will suffice for the next 10-15 years.

Commissioners approved the expenditure unanimously and decided to take funding out of the county’s contingency budget.