I. Stormwater Runoff Reduction

 

I. Stormwater Runoff Quantity Reduction
Reducing the quantity of stormwater runoff from developed areas can help:

  • Restore the natural hydrologic cycle by promoting groundwater infiltration
  • Reduce effects of erosion, flooding, and habitat degeneration downstream

Individuals can reduce runoff quantity by capturing and collecting runoff and by re‐routing runoff to flow to pervious surfaces before it enters the storm water drainage system.

II. Downspout Extension/ Redirection
Downspout extension/redirection is a simple method to reduce storm water runoff. Simply modify existing downspouts to direct the flow of storm water runoff to permeable surfaces on the property.

Downspout flow directed toward cobbles over dirt.

    Benefits:

    • Redirects runoff to functional landscape features
    • Keeps stormwater runoff on the property
    • Downspouts can be redirected to rain barrels and cisterns for collection and later use of stored rainwater
    Installation:

    • Check for city permitting If downspouts are connected to a storm sewer system or underground drainage system before making modifications
    • Calculate necessary landscape area for runoff collection based on roof area, e.g. roof area sq. ft. x 10% = landscape area sq. ft.
    • Cut downspout near base with hacksaw
    • Insert downspout into elbow(s) at base of downspout to direct runoff in the desired direction
    • Cut downspout extension to desired length and attach downspout extension to the opening of the elbow
    • Place splash plate below the end of the downspout extension to dissipate the runoff and prevent erosion
    Important considerations:

    • Add or remove soil to ensure runoff flows away from structures
    • Do not redirect or extend downspouts onto slopes greater than 10%
    • Downspout extensions must extend at least two feet from houses without basements and at least 10 feet from houses with basements
    • Make sure there is enough permeable surface for the runoff to percolate into
    • Extensions must be at least five feet from neighboring property
    • Avoid placing extensions in locations where they will create an unwanted obstacle

III. Rain Chains
Rain chains are a replacement of a normal downspout with a functional and artistic chain device. The rain chain sends runoff to the surface below the roof for water collection or percolation.

Rain Chain

    Benefits:

    • Can be used to capture water in a clay pot or bowl at the bottom of the chain
    • May be used to dissipate storm water runoff into gardens or lawn by placing stones, pebbles, or a splash plate at the base of the chain
    Installation:

    • A metal v‐shaped clip is placed in the downspout hole of the gutter where the original downspout has been removed. The rain chain is connected to the bottom of the v‐shaped clip
    Important considerations:

    • Rain chains should be connected to gutters on overhangs extending at least three feet from the house (an elbow system may be used for houses without overhangs)

IV. Rain Barrels
Rain barrels are an easy stormwater harvesting device used to collect stormwater for irrigation and other yard needs.

Rain Barrel

    Benefits:

    • Reduces stormwater runoff
    • Saves on municipal water usage
    • Can be used for watering lawns and gardens
    • Rain barrel water is healthier for plants than “hard” water coming from the tap
    • Stored water can be used during dry months and droughts
    • A low cost and effective means of storm water retention and detention
    • Adapt the rain barrel to create a drip irrigation system for efficient garden watering
    Installation:

    • Place cement blocks or a rain barrel stand where you intend on placing the rain barrel. By raising the height of the barrel you will get more water pressure.
    • Cut or disconnect downspout taking into consideration the space needed for attachments (elbows etc) or use a Garden Watersaver to divert downspout water to the rain barrel (the Garden Watersaver downspout attachment collects water and diverts it to the rain barrel until the rain barrel is full, at which point backpressure occurs and the water flows through the downspout into the rain barrel)
    • If not using a Garden Watersaver downspout attachment, attach component downspout extension to surface of rain barrel
    • Attach a spigot at the bottom of the rain barrel or a hose to the garden
    Important considerations:

    • If not using a Garden Watersaver, connect an overflow hose to the top of the barrel to prevent damage to the house or foundation
    • Place a mosquito screen at intake to the rain barrel and use some precaution such as screwing the lid to the barrel to prevent a drowning hazard to children and animals
    • Place warning signs on the barrel indicating that the water is not potable

V. Rain Pillows
Rain pillows are storm water collection devices similar to rain barrels with the added features of larger storage capacity and water filters and pumps. They provide debris‐free water for more applications due to the added pressure from the pump.

Rain Pillow

 

Rain Pillow Pump

    Benefits:

    • Same applications as rain barrel plus additional benefits from pump which can accommodate drip irrigation, garden sprinklers and car washing.
    Installation:

    • Choose a location for the rain pillow near a down spout and beneath a patio or in a crawl space of the foundation
    • Disconnect or modify downspout for attachment to the rain pillow filter
    • Connect secondary overflow drains near filter and near pillow to lead away from the house and foundation
    • Connect pump to water pillow and direct flow to hose or drip system

VI. Cisterns
Cisterns are rainwater catchment systems that provide larger quantities of water for later use than both rain barrels and rain pillows. They are similar to rain pillows in that they commonly have a water pump used to distribute the water, although gravity distribution works also. Cisterns can be used to provide water for non‐potable plumbing uses, such as toilet flushing, in addition to irrigation.

Cistern

Cistern Placement

    Benefits:

    • Reduces storm water runoff
    • Saves on municipal water non‐potable usage
    • Can be used for watering lawns and gardens or if connected to the plumbing system can be used for toilet flushing
    • Cistern water is often healthier for plants than “hard” water coming from the tap
    • Stored water can be used during dry months and droughts
    • A low cost and effective means of storm water retention and detention
    • Can adapt the cistern system to create a drip irrigation system for efficient garden watering
    • Reduces the peak flow volume of runoff that would otherwise contribute to flooding and erosion in storm water drainage systems
    • Generally holds a greater volume of water than rain barrels
    Installation:

    • For systems not connected to the plumbing system, the installation is very similar to that of rain barrels. Systems connected to the plumbing require more installation.
    • Decide the size of storage unit based on precipitation input, outdoor/indoor water demand, and the minimum runoff reduction level to attain an approximate natural hydrologic cycle for the area
    • Location of cistern should be on level, stable and firm surface. They may be placed on roofs, below ground surface, above ground surface or below patios or crawl space.
    • Modify downspouts to redirect and/or extend downspouts/piping to the cistern
    • Screens should be fitted into the top of each downspout, diverting water to the cistern
    • First flush diverters or roof washers can be constructed to avoid filling the cistern with contaminated water from a first flush (a first flush diverter is an upstream downspout from the cistern which fills with the first flush before allowing water to flow into the cistern; a roof washer is a filter box placed just prior to the cistern, which filters out finer suspended solids for house‐hold use or drip irrigation)
    • General components for a cistern disconnected from the plumbing system:
      • Screened gutters, downspouts, and piping
      • A fully closed storage tank
      • A spigot or hose for access
      • An overflow outlet
    • General components for a cistern connected to the plumbing system for toilet flushing:
      • Non‐toxic, fully screened gutters, downspouts, and yellow pipes
      • An automatic self‐draining first flush diverter
      • A fully closed storage tank designated as safe for potable water use by the FDA
      • An approved backflow prevention device and an air gap to secure the city municipal water system from backflow of non‐potable water
      • A spigot/pump for access
      • An overflow pipe
    Important considerations:

    • Consider constructing cisterns at least 10 feet from the house in order to avoid damage to the building or foundation (overflow should lead away from house and cistern)
    • For a cistern connected to the plumbing system for flushing toilets, a plumbing and building permit is probably necessary (check the Department of Building Inspection)
    • Cisterns should have tightly fitting covers to prevent contamination from animals, and in the case of above ground tanks to avoid penetration of sunlight which will lead to algal growth
    • Gutters, screens, and cisterns should be monitored for debris regularly
    • When interior of tank is cleaned, use a concentration of 1 cup bleach to 10 gallons of water to rinse inside of tank
    • Cisterns should be labeled as non‐potable (not safe for drinking), unless proper treatment processes are implemented
    • For technical assistance see references

VII. Rain Tube
Rain tubes act as simple filters to keep gutters and therefore harvested rainwater free of large debris.

Rain Tube

    Benefits:

    • Appurtenance of a well functioning rainwater catchment system
    • Prevents clogged gutters and downspouts by only allowing rainwater to pass into gutters and deflecting debris
    • Made to fit any rain gutter
    • Made from 100% post‐consumer recycled food‐safe material
    Installation:

    • Rain tubes will fit any rain gutter
    • Rain tube suppliers will install the rain tube for customers (see resource pages for information on local supply stores)