Disasterous Draining of Kilpatrick Pond

VIDEO LINK:
http://www.youtube.com/watch?v=1j-fZyl38JY

I was able to attend all of the meetings with the Blaine County Commissioners concerning the stream alteration permit application for the Kilpatrick Pond area of Silver Creek by landowner Purdy and The Nature Conservancy.  Purdy's proposal was to build a temporary coffer dam across a portion of Silver Creek and divert all of the stream into an irrigation ditch. This would de-water and dry up the lower section of the pond, so that the heavy equipment could then build a new island, fill in the banks to narrow the stream, and build a new dam. Upstream of this coffer dam, water levels were to stay at a sustainable level. This was to mitigate downstream sediment transport.

The Purdy proposal was to only de-water that section of Silver Creek downstream from the temporary coffer dam, which is the construction area.

This has not happened. Other methods were used in order to divert Silver Creek into the temporary ditch lined with plastic. Unfortunately, this alternative method de-watered all of Kilpatrick Pond at once, including upstream to Kilpatrick Bridge and beyond. In fact, it has de-watered the float tube area upstream of Kilpatrick Bridge for approximately  four hundred yards. It has also drastically lowered the stream levels through the S- Bends and, more importantly, almost dried up the Lower Slough. This is a natural spring fed slough that connects to Silver Creek.  I walked the Lower Slough today and found many large trout stranded in a few deeper pockets. It appears that they will not be able to migrate back into Silver Creek. Unless there is a fish salvage conducted by the State of Idaho Fish & Game, no doubt these trout will perish.

                                                                     Lower slough

                 
                        Downstream of Kilpatrick Bridge, sediment flowing downstream. 

Because the coffer dam was not used to keep pond water levels stable while diverting Silver Creek, massive amounts of sediment have now flowed downstream. This is due to a sudden water level drop through the entire Kilpatrick Pond and bridge area, both up and downstream. The small channel that is left has carved tons of sediment out and has moved it downstream of Kilpatrick pond. The water velocity in the left over channel is fast and it continues to carve out more sediment and deepen a channel as long as the water is being diverted into the irrigation ditch. These flows could continue for weeks.

                                           Upstream of Kilpatrick Bridge, high turbidity

This just goes to show that there was not correct oversight by  permitting agencies inspectors. Its a tragic loss of habitat, namely the aquatic invertebrate populations in a large area of Silver Creek. By drying up this entire section of Silver Creek at once, most all invertebrates have certainly perished. I estimate there is only 5% of the pond area left with with water flowing through it.

                          Looking upstream of Kilpatrick Bridge towards the S-Bends

The sign below was posted after the SAP permit was issued by our Blaine County Commissioners.  The Purdy SAP is being self contracted by Purdy in partnership with TNC. TU jumped on board and appointed themselves as the overseers of this disastrous project.

                                         A self proclaimed enhancement project

A recent email from a civil engineer in Boise after viewing the photos in this post:
 

The Army Corps of Engineers should be contacted, and the EPA, State office. If one of my public works projects created turbidity like that in a surface water, there would be very stiff fines assessed to the permit holders.  Just flat crazy.