Notes from a brief presentation with excellent examples of design for drought and flood:
Front Range Bioneers, November 7-9, 2014
Local Plenary: Jason Gerhardt, Permaculture Design for Drought and Flood, Saturday, 11/8, 11-11:15am
Look at problems in terms of how I can integrate ecologies and communities.
Can we design water systems that improve ecology? Focus on infiltration. State of Colorado water laws based on certain amount of water flowing downstream. 2007 study in Boulder County: 3% of water makes it to the stream, other 97% evaporates. Perennial state of drought. Growing population. Overtaxed system, over appropriated rivers. 50% of water coming from other side of Continental Divide. Drought/flood dichotomy.
Runoff from cities: overland flow, soil erosion, losing organic matter and ability of landscape to store water. Pollution. Downstream flooding. Runoff leaves dehydrated landscape. All the water of the flood did not do any ecological good. Pre-development, it was able to infiltrate the landscape.
Design for drought: we manage water sources, conservatively. We also look at the sink, how we get the water off the surfaces as soon as possible. We don’t have a runoff problem. We have an infiltration deficiency.
Residential landscapes. Street runoff. Every street is water conveyance surface. Capture in street-side gardens. Capture as close to where it falls as possible.
Parking Lot Green Infrastructure.
Contour Log Felling. Apply to wild spaces, especially in burn scars. Lay logs perpendicular to slope, and water, soil, seeds will collect behind that log. Forest will regenerate.
Check dams. Rock dams that slow water and allow it to back up and soak in.
Water Runoff & Water needs. Seven houses on Boulder cul-de-sac, Quarry Court. Client on the block asked, can you calculate surface area of all these roofs streets and homes? Can all homes be taken off irrigation? Result: More water falling on that landscape than all those houses use in a year. Drought proof landscape and flood preventing by changing the way we design landscapes. Trees planted in basins.