About SmartStorm®

SmartStorm® was developed by the Charles River Watershed Association (CRWA) in response to threats faced by the Charles River and the citizens who rely on the river.  Ongoing development has increased demand for drinking water drawn from the watershed while an increase in impervious surfaces such as roofs, parking areas and roads has disrupted the natural replenishment of groundwater.  In many towns, storm water that once sank through the soil now runs into street drains to be combined with sewage. The combined effluent is then treated and piped out of the watershed. Meanwhile residents water their lawns and gardens with water drawn from the ground or with municipal drinking water. The combined effect of these events is an increased volatility of stream flow and a general decrease in the quantity of water in the river.

After studying the river and documenting this trend for many years, CRWA developed a strategy to protect the river and its watershed. The principal goal is to keep water local, so that less water is piped to where it is needed and less water is piped away from where it originates. As the largest and oldest organization devoted to watershed protection in the country, CRWA has long been a leader in creating and exporting new protection methods and technologies. SmartStorm is a good example of a system that has wide application. A SmartStorm System is intended to offer the following benefits:

1. Provides a “usable” amount of water for watering or other outdoor use by collecting and storing rainwater in large tanks, thus decreasing the need for other sources of water.
2. Prevents runoff of roof water into storm drains or into rivers and streams, thus decreasing combined sewer overflows or stream flow volatility.
3. Helps recharge groundwater sources so that more water is available to keep rivers running and wells producing during dry times.
4. Helps to re-direct storm water away from foundations where it can seep into basements and cause damage.

How SmartStorm Works

Each SmartStorm System is customized for the location where it will be installed. However, each system includes the same basic components and has the same requirements. Rainwater is collected in gutters and is filtered before being stored in large 400 gallon tanks. An electric pump connected to a garden hose is used to access and distribute the water. Any excess overflow as well as all water during the winter is directed to a drywell that discharges it underground. The siting and number of tanks and the size of the drywell needed are dictated by the size of the roof and nature of the grounds.

Description of SmartStorm Components

Collection and cleaning

Rainwater entering the system is collected from the roof.  Gutters and downspouts are needed for this but are not included in the SmartStorm installation. It is best to site the storage tanks as near to a downspout as is practical. Modification of existing downspouts to redirect flow to the storage tanks is part of the installation process. Often a system will initially collect water from just one downspout. Later on additional rainwater can be directed to the system by modifying gutters and/or downspouts. Roof water typically contains a fair amount of large detritus from the roof such as leaves, as well as smaller particles such as pollen and dust. To prevent these contaminants from entering the system a number of cleaning steps must be taken. First off, it is a good idea to have standard barriers installed on gutters to keep out the majority of leaves.  The next step is a self cleaning screen at the base of the downspout. Water exiting the downspout falls through into the tank while debris is washed off the open end.  Finally, water enters the tank through a fine mesh bag sealed to the tank with an aluminum frame. This serves the added purpose of keeping insects such as mosquito from entering the tank to breed.

Storage

Rainwater is stored in a series of interconnected 400 gallon tanks. Each tank is approximately six feet tall and four feet wide. The tanks are made from heavy duty dark green polyethylene, roto-molded and containing a UV inhibitor.  The tanks were designed to be strong enough to stand alone above ground or be completely buried. Standard installation calls for the tanks to be buried five feet into the ground.  The top section can be removed for inspection or periodic cleaning.  For safety, each tank lid is attached with stainless steel tamper-resistant screws. Inside the tank a removable platform prevents anyone gaining access to the tank from falling to the bottom.  The tanks are connected to each other with three inch PVC pipe and special seals to prevent leaks. Any number of tanks can be strung together and will fill simultaneously.  These tanks were designed and manufactured in Massachusetts specifically for this application.

For locations where visible tanks are impractical or undesirable a different storage configuration is available.  An area is excavated and an underground storage container is created using RainTank® Modules surrounded by a heavy duty liner.  Once the area is covered it can withstand heavy traffic or even structures. 

Water Retrieval

Two types of pumps are available for use with the system.  The first is a standard shallow well jet pump with a pre-charged pressure tank.  This is the type of pump many homeowners use for domestic water wells.  The pump automatically turns on whenever a faucet or hose end is opened for use.  This pump works best where it can be installed indoors as it must be protected from the weather.  A second type of pump is the all weather stainless steel sprinkler pump.  It is smaller, lighter and less expensive.  It does not include a precharged tank or pressure switch. Water flow is controlled by turning the pump on or off with its weather- proof switch. Both types of pumps require a 120 volt GFIC outlet with a weatherproof cover. Consult a qualified electrician to install the outlet as it is not included in the SmartStorm package.  Both types of pumps are controlled by a pressure sensing switch that prevents the pump from operating dry.

Groundwater Recharge

After a rain event has filled the storage tanks, additional rain water is directed to an internal overflow system and is piped to a special drywell.  The drywell is made from 100% recycled plastic, formed into a structurally strong matrix.  A drywell “unit” is approximately 1 cubic meter in size and is 94% empty space.  A series of units form a larger block that is wrapped tightly in heavy duty landscaping fabric.  The entire assembly is buried and connected to the storage tank with three inch PVC pipe.  When properly covered with soil, the drywell is invisible, very efficient and can withstand the weight of vehicles above.  The drywell system we use is manufactured by Atlantis, Inc. under the name RainTank®. More information on this product can be found at Atlantis.com.  A valve in a storage tank allows all water entering the system during the winter to flow directly to the drywell.  The tanks can also be drained in the manner for cleaning and inspection.