permaculture

["Lawrence F. London, Jr." <lflj@bellsouth.net>]

Purification of pond water(irrigation, aquaculture, holding, habitat) with bottom sediment stirring and distribution to 
feed aquatic plants floating on surface:

John Todd at NAI and Ocean Arks International probably employed this technique and Elaine Ingham of Soil Foodweb 
suggested doing this to aerate and purify manure lagoon water to be used for fertilizer. She suggested looking at
certain equipment manufactured to do this job. A type of submersible pump would 
"crawl" the pond or lagoon bottom
excavating, liquifying and aerating sediments on the bottom and pumping them up to the pond surface where the nutrients 
can be utilized by floating aquatic plants and plants in the shallows such as cattails, reeds, water hyacinth, papyrus, 
water lillies, duckweed and algae.

I have three wet weather ponds that collect and hold most of the runoff from my property. This includes overflow from 
gardens, roads, fallow fields and yards. We have had over three months of drought this year with only about 2" of 
rainfall, total. The pond with the lowest water level has a dense population of duckweed. The other day I threw a rock 
into the water to try and gauge depth. Two days later I noticed that the turbulence caused by the rock
had disturbed nutrient-rich sediment, causing it to mix with water and flow into the surface area. There was intense, 
fresh growth of algae and duckweed at that spot; I could easily see the darker green color of the newly fertilized area.

What equipment is available to use to treat ponds of various sizes and depths using this procedure? Smaller, slower 
units that are solar or wind powered would be ideal. These could be moved by hand from one location to another and 
eventually cover the entire pond bottom.