Pond / Alternative Water Supply
Last Updated: December 17, 2008
Most recent images first; plan drawings, text and additional references at bottom...

And in 2007 we added a small floating platform to the pond.

 

The pond was filled by mid-November, after the 2nd rain!

 

Pond siphon for the berry garden farther down the property (also for backup potable water and maintenance). The siphon runs under the concrete-fortified spillway.

 

Bypass spillway (for 100+ year floods, sited 3-1/2" above primary outlet culvert)

 

Pond spillway with concrete giving way to a rock-lined channel and emptying into the original (natural ravine) drainage.

 

Concrete armor around culvert (pond side, outpour into original/natural ravine with rock bed silt trap)

 

Setting the no-seep collars that Brian fabricated around the primary outpour culvert

 

 

 

 

The 'dig' is nearly complete, note boulders sited (pulled from pond during the dig)

 

Starting the 'big' dig (here they are starting the main dam's keyway)

 

The Pond

A pond is a wonderful way to cool off on a hot summer day. Yet it is also a place of nature where amphibians and water plants thrive and where migratory animals and birds stop, gracing us with their presence. On a lesser note (to some), it is also a backup water supply. Should a well go dry or the output be reduced (e.g. by over use or by earthquake), a pond can see a family or farm through...

We started our pond design by walking the land during the winter, noting the flow of water, the lay of the land and the paths of the animals across it. As the spring came we looked at the natural watercourses (ravines, not year-round streams) for what types of native life lived there. Once we had a good site in mind, we then examined the watershed that fed that area. This is important for too little area will not support a pond and too large can cause catrostrophic results without elaborate engineering. In the end, our pond ended up with a capacity of ~0.8 acre feet (~250K gallons) and is fed by a watershed just under 5 acres in size.

A word about building a pond, legally. Our pond required applications (and in cases, payment of a fee) to the following agencies: California Department of Forestry (CDF), Fish and Game (the prime overseer), State Water Resources Control Board, North Coast Regional Water Control Board, US Army Corps of Engineers and the Mendocino Building Department. Fish and Game is the primary obstacle, and even though the pond is sited in a dry ravine, Fish and Game considers it a class 3 stream and classified it as an 'unknown tributary to the Eel River'. Ironically, any flow in our area would end up in the Eel River, regardless of the pond construction. As to the type of application it was for a 'small domestic use' which encompasses small scale agriculture as well as backup water for homesteads. As water becomes more critical, the issue of pursuing permission (whether or not to) will become mute as all water resources will eventually become controlled by the state. In our opinion it is better to ensure a standing water right than to find later you will be billed for the water appropriated...

 

Plans
Adobe .pdf format

Topographic Plan
Primary Culvert
Backup Spillway

 

Additional Reading for Those Interested:

Earth Ponds, Tim Matson, Countryman Press, 1982/1991
Water for Every Farm; Yeoman's Keyline Plan, Ken Yeoman, 1993, Keyline Designs