I am new to this forum and I apologize for the lengthy post.
I have purchased a few acres south of Lincoln, Nebraska to build a house on and I want to build a pond. The primary objectives for the pond will be swimming and providing a nice view. I currently am not a fisher, but I assume I need fish for improved water quality. Also, my kids would enjoy fishing.
My pond design is shown on the attached pictures. My current design was developed based on the following:
-Water quantity. The pond area is approximately 4,000sf and the pond capacity at the maximum level is approximately 106k gallons and the 70k gallons. I plan to maintain a minimum operating depth of 8 feet using rural water and supplement the rural water with runoff from 1.2 to 2.2 acres (depending on what my neighbors do for grading).
4,000 sq. ft. is 100'x40' That is 0.0918 acre. If the average depth is 8', then there will be 239,376 gallons of water in it at that average depth. (325,851 gal in an ac/ft of water)The maximum water level is 1.5 above the minimum operating depth. The volume of water that is contained by the settling basin upstream of the pond is approximately equal to the volume between the pond's min. op. level and the maximum level. I plan to minimize seepage by construction of 6" thick compacted clay liner using the native clay soil.
General pond building practice is to make an 18" to 24" thick clay liner consisting of 6" to 8" lifts of clay, each propery compacted with a sheepsfoot roller before adding the next lift.-Water quality. I plan to treat the runoff with a settling basin. The basin will drain into the pond with an 8" pipe. A flow reduction structure/trash screen will be included to keep debris out of the pond and keep the runoff in the basin for approximately 24 hours. To treat the water in the pond I plan to pump it through a constructed wetland filter. The wetland filter consists of two cells. Both cells will be 12' wide, have an 18" rock base, have an operating depth of 6" above the rock, and have numerous wetland plants. A submersible pump will be used to pump the pond to the base of the rock base in Cell #1. The water will be pumped to a perforated pipe to evenly distribute flow. I have chosen a pump that will pump at approximately 3,500 gph. This will cycle the pond through the filter in approximately 20-30 hrs depending on the pond level. Cell #1 will spill into Cell #2 and Cell #2 will spill into the pond. The total wetland area is approximately 450 sf. I also plan to plant wetland plans around the entire perimeter except for the beach area to help with water quality. I assume certain fish will help with water quality but I have no idea what fish I need.
My main questions are will my side slopes be stable and will my water quality efforts be adequate to keep algae away.
Slopes steeper than 3:1 are difficult to walk out of, and create a pucker factor if they need to be mowed. Good clay soils can be stable at a steeper grade, but then you get into what the construction equipment can safely negotiate while compacting the pond basin.
Clay on the bottom of the pond can easily be put into suspension, and depending on the electrical charges in the water can take a very long or a short time to precipate out. Read http://wildlife.tamu.edu/files/2010/04/4_Control_of_Clay_Turbidity.pdf for more information. If your goal is to have a swimming pond and not a fishing pond, then I would only stock Fathead minnows in the cells and a few Redear Sunfish in the main pond. I would also consider covering the clay bottom of the pond with sand or pea gravel to help prevent clay turbidity. Without going and digging thru my notes, I can't comment on the size of the filter cells. Any comments or suggestions would be greatly appreciated.
