Planning a Rainwater Collection System

Steel Tank Residential_watermarkedWhen planning a rainwater collection system, consideration of annual, monthly, intensity and frequency of rainfall must be taken into account. Precipitation information is generally available by most counties, state climatologists, the National Oceanographic and Atmospheric, Administration (NOAA) and the National Climatic Data Center.

Rainfall amounts in a given location can vary from month to month as well as intensity and frequency. Precipitation reports typically include snow as well as rainfall amounts. A history of rainfall amounts with consideration of a 50 or even a 100 year event are often required by the permitting agency to control overflow and runoff.

Rainfall intensity is measured in inches of rain per hour (IPH). Rainfall intensity will determine the choice of collection components and storage amounts. Although “first flush devices” are widely promoted by permitting agencies and some designers, they may not be the best option. If a given location has a low IPH, a first flush device may not be the best method of pre filtration upstream of storage.

Rainfall frequency can be obtained by a local climatologist and taken into consideration of storage and conveyance. Frequency of rainfall for a given area will help determine storage, as well as pipe size used for conveyance.

Rainfall return period is the historical data of a rainfall in a given location. While not a representation a specific time period, a return period determines the probability of an equal event in a given time. In other words an event of a 2-year return period has a 50% chance of occurring in any 1 year period.

Lastly, a maximum amount of dry days is critical in the design of a successful rainwater collection system. An historical account of dry periods is essential in determining storage capacities to get through the dry months.

Careful review of local rainfall data in determining size of storage, conveyance, and components is essential in a successful rainwater collection system.

Continuing Ed For Rainwater Pros in Vancouver WA

arcsaDo you know that rainwater harvesting professionals can get their nerd on through educational opportunities, brought to us by the American Rainwater Catchment Systems Association (ARCSA)?

ARCSA’s mission is “to promote sustainable rainwater harvesting practices to help solve potable, non-potable, stormwater and energy challenges throughout the world.”

In addition to informative articles and other information about rainwater collection, ARCSA offers training and development opportunities for RWC professionals to achieve industry accreditation.

ARCSA and Washington State University Extension and Clark County are offering a comprehensive Rainwater Catchment Accredited Professional training course (please click to register), on August 21 & 22, 2015 at the Heritage Farm in Vancouver, Washington.

According to ARCSA’s recent email: With the ongoing water crisis in California, and now the Pacific Northwest, this workshop will focus on the Oregon and Washington Issues. Residents of the Pacific Northwest are encouraged to attend to learn to capture stormwater, while creating additional “reservoirs” to store water for future beneficial uses. You can’t use it if you don’t store it.

Be sure to follow ARCSA on Twitter and Facebook for important updates about California and Washington drought conditions, or sign up for their mailing list to receive emails about rainwater harvesting and educational opportunities.

Animas River Toxic Spill Poses Serious Health Risks

animas-river-pollutionThe August 5th Animas River spill is now delivering serious health risks to three states – Colorado, New Mexico and Utah. Our recent blog post details how the orange colored, contaminated water could be seen working its way toward New Mexico and now, today, the U.S. Environmental Protection Agency announced that “surface-water testing revealed very high levels of lead, arsenic, cadmium and other heavy metals as a sickly-yellow plume of mine waste flowed through Colorado.”

The AP story further reports, “Over the long term, these metals can seep into the surrounding water table, potentially polluting drinking wells. The EPA has offered free water testing for homeowners with wells close to the river, but it’s unclear how long that offer stands.”

CBS News reports “Toxicologists say those people who live along the Animas River could be ingesting the contaminated water in any number of ways, such as drinking it or showering in it.”

As we talk about heavy metals being released into our waterways, the keyword here is HEAVY. While some will flow and be naturally flushed away, a great risk is that toxins will sink to the bottom and remain in the water, continuing to contaminate even after the yellow color dissipates and the water begins to appear to be normal.

In its article Rainwater Harvesting Can Create Safe, Decentralized Water Supplies, The American Rainwater Catchment Systems Association (ARCSA) reports, “A well-designed, installed and maintained rainwater harvesting system can provide significant amounts of high-quality water for potable and non-potable, residential and commercial use. Even in the arid Four Corners area of this spill, ample water can be harvested.”

It’s time for all states to begin allowing rainwater collection for potable and non-potable use, so individuals and businesses can harvest water for their own health and well being.

Animas River Pollution Photo courtesy of Snopes