All the guides I have read about building drainage trenches have all said to use drainage rock or gravel as filler. There are other options available on the market, such as a plastic matrix media, but using rock chips or rounded river rock appears to be the most common solution.
But how much space does that rock take up? How much volume of water would I lose?
First part of this series covers different design ideas for handling urban runoff on single family, multi-family and commercial developments. This is part 2.
Continuing from the Santa Monica Urban Runoff Management Program, this section covers their worksheet for a variety of construction activity or for voluntary participation.
Check with your local city to determine their stormwater treatment requirements on new or redeveloped construction. In some cases, changing 2,500 sq ft of pervious ground to 2,500 sq ft of impervious ground can trigger the need for stormwater treatment construction at the job site. The Federal Clean Water Act, enforced by the State Regional Water Boards mandates this requirement. In many cases, a regional “Municipal Regional Permit” will hold the design requirements for following through.
City of Santa Monica URMP
In the southern California city known for its nice beaches and celebrity homes, Santa Monica has an Urban Runoff Management Program aimed to reducing runoff from polluting Santa Monica Bay. In a city Ordinance Chapter 7.10 that was designed to reduce 0.75″ of rainfall leaving all “impermeable surfaces of all newly developed parcels within the City. … also specifies guidelines for existing properties to reduce the level of contaminants that are carried by urban runoff into the Bay.”
In their Urban Runoff Management Program brochure, they expand upon Best Management Practices for reducing urban runoff pollution. Information includes “increasing the percentage of permeable surfaces and landscaped areas by”:
- porous materials that will increase the amount of runoff that seeps into the ground, rather than being carried into storm drains
- natural drainage
- filtration pits
- swales, berms, green strip filters, gravel beds and french drains.
Oil runoff into a storm drain.
Every time it rains, water is always seen running down street gutters, into storm basins and eventually flowing back to the ocean. Carrying away pollution and nutrients from our landscapes.
Businesses and government organizations have been working to reduce urban run-off and it is time to homeowners to join the effort and help the cause. Why? Because it is the right thing to do. Continue reading
Credit: D&S McSpadden
As we’ve learned about the growth potential associated with recycled water, rainwater has its own magical attributes too.
“Despite all our accomplishments, we owe our existence to a six-inch layer of topsoil and the fact it rains.” – Unknown
A gift from the heavens and responsible for all life on the planet, what is so special about rainwater that you won’t find in drinking water or recycled water? Lets analyze the three.
Earlier last week, the National Weather Service in Sacramento held a weather chat on Twitter as an atmospheric river event was going to be barreling down on California. It was open to anyone to ask a meteorologist a question. I asked (on my personal Twitter account):
“When this storm passes, is it possible to calculate how much water fell across the state? #cawx”
@NWSSacramento’s video response:
Water storage in Texas.
California usually sets the stage for policy when it comes to environmental issues. When it comes to rainwater harvesting, we are far behind. As we face this drought to drench, we should have the drive and motivation to capture as much rain was we can. Even with reservoirs rising 391 billion gallons after a storm, we’re still short of average for this time of year.
Many call for building more dams or raising their levels to store more water – but all of that comes at a price and an environmental impact.
To put things into perspective, think of this call-to-action as de ja vu. Back when installing photo-voltaic panels (solar panels) on homeowners roof’s was something deemed unworthy has now turned into a economic boom for the state. Nearly every neighborhood has dozens of homes covered in panels. Those power generation stations were funded with tax rebates. Rainwater harvesting should be no different.
You may have noticed an abundance of rainwater harvesting articles as of late. There is a reason for that. Water that falls from the sky is yours to do with. It would be wise to keep it on your property and put it somewhere that won’t affect the foundation of your house. The best place to put it is in the ground, where plants can utilize its resources later in the year.
The fundamental principles established here are exactly what people have done for centuries.
Percolation. This may be new rainwater term to most homeowners, but it is a term and activity that we need to embrace. Simply put, it refers to keeping rainwater on the land and letting it flow into the ground, ultimately replenishing ground water.
An inch of rain falling on about 1600 square feet of rooftop will produce about 1,000 gallons of run-off. Capturing this water on the property at the start and end of the rainy season will lessen irrigation needs and help plants cope with drought conditions.
Capturing rainwater is easy to do. All you need is rain and a bucket. Capturing rainwater for re-use in the yard becomes helpful when using large containers and rain gutters from your roof. A 1,000 square foot roof will capture about 625 gallons of water when an inch of rain falls. For a 1/4″ to 1/2″ rain storm, those totals can quickly add up to 150-300 gallons of water, significantly more than my rain barrels hold.
When its not raining and the barrels are full, it becomes an excellent source of water for irrigating the plants in the yard, providing savings on potable water use at home. Plus, rainwater doesn’t have all the chemicals in it that you find in the normal drinking water supply.