Information and resources for the transition
from shedding to infiltrating stormwater
On this page:
|$1.99 Stormwater Rainbomb video full version, lo, med and/or hi res|
Video of a 2.5" storm on Jan 31st, 2016, which included a 3 inch/ hour burst for 15 min. That's a 10 year storm; the biggest of the season.
The video has synchronized time lapse of the inlet, storm radar, gutter cam, and graphs of rainfall intensity, gpm of rain income, run-on from roof, road, and hillside, infiltration and the mere trace of runoff. Yes, this took forever to dial in. The water income peaked at 1500 gpm, infiltration at about 1000 gpm (!). We infiltrated about 67,000 gallons in six hours…equal to 9 months consumption for the house. The whole thing was pretty amazing. I had high expectations and the performance exceeded them. Learned a lot about best practices for stormwater infiltration. Check it out:
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|$1.99 Stormwater Rainbomb video full version, lo, med and/or hi res|
Optimizing stormwater management is the perfect gateway for government systems thinking and collaboration across numerous departments (for more on this see the Event Handout).
This was a demonstration of the under-appreciated potential for small-scale, distributed catchment in developed areas to:
- transform the hydrology of the landscape
- increase water supply
- reduce downstream flooding
- increase dry season creek flows
- increase readiness and resiliency for both flood and drought
The demonstration was attended by 30 professionals including our state congressional delegation, the heads of several local water-related agencies, local non-profits, educators and students.
|$1.99 Stormwater Infiltration Demo full version, lo, med and/or hi res|
- 70,000 ft2 of catchment
- An inlet capable of 3500 gpm peak inflow
- 4000 ft2 of simple, mulch-filled infiltration terraces, basins, and swales of a variety of designs, on a 10,000 ft2 (quarter acre) lot
- Monitoring wells 8' below the surface and about 30'± horizontally from the upper infiltration basins
- 500-1000± gpm of continuous infiltration capacity
- 12,000± gallons of surge capacity above ground
- 100,000± gallons of surge capacity in three feet of sandy topsoil
- 35,000±gallons of long term storage in the topsoil
- Target capacity: infiltrate 100% of a 400-year peak rain intensity event ("rain bomb") like this one below, from an area six times the size of the property
The hydrograph for the most intense rainfall in the Flood Control Historical record for our area (1.2" in 15 minutes), on December 11th 2014. The expected recurrence interval based on pre-climate change patterns is once every 400 years. Vertical axis is inches per five minute interval.
- Help develop engineering values and best practice details for small scale, infill stormwater infiltration suitable for developed areas of California
- Help increase the accuracy of estimates of possible contributions to local water and state water budgets, 1) for conservation downstream of the meter by offsetting the need for irrigation with metered water 2) for increased groundwater recharge upstream of the meter
- Help increase the accuracy of estimates for the possible contribution to flood control, dry season habitat flows, etc.
Water at 177 gpm fills the first three terraces, then overflows with a two-second surge of 2000± gpm.
1240 gallons in 7 minutes only wet the first 15% of the infiltration basins. (Note: this makes 2000 gallons we've added to this small area in a week and there is still no moisture in the monitoring wells twenty feet away and 8 feet deep, indicating that the water is going down rather than sideways.)
Discussing the implications...
Later, in the rain--
Home water budget before/ after water makeover, impacts on water and climate commons (excerpt from Create an Oasis with Grey Water (book)
The California Water Resources Control Board is currently soliciting feedback on their strategy to optimize the management of stormwater in California:
We suggest you e-mail Frances Spivy-Weber at the SWRCB before Jan. 6th and ask that:
1) the SWRCB support the filling of data and best practice information gaps for simple, small scale groundwater recharge projects
2) investigate the potential benefits for development and statewide deployment of software tools to identify and prioritize stormwater management opportunities
An accurate mental model is the basis for good design...and the best way to improve a mental model is by direct observation of water systems, natural and man made. As soon as it starts raining, head outside and observe. Be sure to poke through the surface of the leaf litter and soil. Based in part on spending a month inside a fissured bedrock aquifer in Spain, I think that most of the recharge in such formations may come from a tiny % of the area where the water concentrates, is detained, and has a high perk pathway to get underground...
Most of the increase in groundwater flow due to medium rain from countless bedrock fissures in a 400 year old horizontal well that goes 500' into the mountainside was from just one fissure (The special fissure is behind the brick dam I made above).
Not many flow surges to see recently...except for the 56,000 gpm surge on the Santa Ynez we kayaked this August (!)
Stunning and surreal to see sad pond Cachuma with a pipe to pump the water over the spillway several stories above the water level…then kayak/ paddle board the river for miles on the release of a staggering quantity of crystal clear, warm drinking water…
Same day, below the dam. Note dead cattails…this was sun blasted dry rock a few weeks ago and probably a few weeks after...
Riverside wells were pumping full speed to get as much of the water as possible before it could reach the water rights holders downstream.
- Stormwater floods Modesto almond orchard in experiment to restore aquifers
- What Singapore Can Teach All Cities About Using Urban Green Infrastructure To Mitigate Megadroughts ...LID (rain infiltration) in Singapore contributes 35 percent of the city's water supply, with much of it integrated into innovative architecture as well as landscaping for pedestrian or recreational amenities. Eventually, the city has plans to turn ninety percent of its surface area into rainfall catchment...
- Why Storing Water for the Future Means Looking Underground Conventional dams and reservoirs work against nature. It’s time to work with it...
- After the Lawn: Transitioning to an Integrated Rain Garden
- Stanford Researchers Look to Stormwater as a Solution for Semiarid Regions
- Earth's hidden groundwater mapped: Less than six per cent renewable within a human lifetime
- Less water might be plenty for California, experts say, and conservation is only the start
- Voodoo Hydrology: Pitfalls of Urban Hydrology Methods & What You Need to Know New Webinar Live Jan. 21
- Principles of Ecological Design (article)
- Rainwater Harvesting for Drylands vol.1 (book)
- Water Storage (book)
- Can a 4000 ft2 Home be Green?
- Greywater Site Assessment/System Checklist (PDF)
- Eco Home Checklist (pdf)
- Fecal coliform measurements
- How to measure Perk
- Water quality testing (download)
- Water Calculations Spreadsheet
- Mulch Basins Flyer
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