LID Techniques & Design Guidelines butterfly

There are six Low Impact Development (LID) Techniques preferred for private properties in Pacific Grove. You will find a brief overview of all the techniques on this page:

  1. Roof Downspout Redirection
  2. Creating Rain Gardens
  3. Rain Water Harvesting
  4. Replacement of Impervious Surfaces with Pervious Surfaces
  5. New Tree Planting
  6. Gull Rooftop Deterrents

Resource & Definitions

1. Roof Downspout Redirectiondownspout-1

Roof Downspout Redirection: DETAILED DESIGN GUIDELINES

BENEFITS

  • Free “seasonal’ water for landscape
  • Slows roof/downspout runoff; reducing peak stormwater flows
  • Inexpensive and easy
  • Add a rain chain or bowl for decoration

CONSIDERATIONS

  • Runoff to be routed to a porous landscape, landscape depression, mulch pit, or gravel basin 
  • Overflow to be routed away from structures and neighboring properties
  • Cap downspout connection leading to stormdrain

Additional Resources and Definitions

2. Creating Rain GardensAdding depressed planted areas that rain water will soak into.

rain-gardens1

Creating Rain Gardens: DETAILED DESIGN GUIDELINES

BENEFITS

  • Adds an aesthetic landscape feature with endless planting design possibilities
  • Plants promote native habitat and food source for hummingbirds, butterflies, and honey bees
  • Promotes infiltration of stormwater
  • Slows stormwater runoff; decreasing peak storm water flows
  • Helps clean the stormwater through filtering it through the base material and soil
  • Add mulch and compost for added water retention

CONSIDERATIONS

  • The required size, shape, and depth of  the garden depend on how much water is captured (water should be drained within  48 hours). Ensure you property has enough space available
  • Rain gardens and swales to be located  away from building foundations and on a relatively flat area
  • Overflow to be routed away from structures  and neighboring properties
  • Irrigation will be needed for plant  establishment
  • Select appropriate plants (sun/shade, wind exposure, soil type, CA coastal native plants)
  • Regular landscape maintenance required to meet plant species needs. Regularly check 
  • rain garden has a clear inlet and overflow path
  • Cost varies per the size, planting design and whether a landscape contractor is used For newly installed rain gardens which are mulched, be aware that after a large rain  event, bark may float and clog drains or outlets
  • For larger systems, subsurface drains with base rock and/or an overflow inlet may be needed, this may require professional design and contractor fees for installation

Additional Resources and Definitions

3. Rain Water Harvesting (barrel or cistern)harvesting1  harvesting2

Rain Water Harvesting: DETAILED DESIGN GUIDELINES

BENEFITS

  • Free water for landscape irrigation; reducing the need for potable water
  • Slow roof/downspout runoff; reducing peak stormwater flows
  • Plants prefer rainwater
  • Inexpensive and take little space
  • Easy to expand system

CONSIDERATIONS

  • Maintenance
  • Clean filters
  • Clean tank
  • Screen all vents
  • Prevent algae growth with a dark colored tank
  • Size: tanks with a capacity of 1,500 gallons require a permit
  • Route overflow pipe away from structures and neighboring properties
  • Provide a filter for excessive/large debris from rooftop
  • Non-potable

Additional Resources and Definitions

4. Replacement of Impervious Surfaces with Pervious SurfacesRemoval of paved surfaces that rain flows over and into storm drains.
pervious2

Replacement of Impervious Surfaces: DETAILED DESIGN GUIDELINES

BENEFITS

  • Many types of pervious surfaces and paving types
  • Paver systems are easy to repair or replace
  • Promotes infiltration of stormwater
  • Slows stormwater runoff; decreasing peak storm water flows
  • Helps clean the stormwater through filtering it through the base material and soil
  • Beneficial to street trees as roots can have more access to air and water
  • Pavers enhance curbside appeal and increase property value

CONSIDERATIONS

  • Properly install/compact the base layer
  • to ensure an even surface
  • The depth of the base layer and
  • reinforcement should be considered based
  • on the type of load the pavement will receive; installation by a certified contractor may be required
  • Be aware of underground utilities
  • Install pavers with the correct joint spacing
  • Pervious concrete or asphalt may
  • require vacuuming over time
  • Typically more costly on large scale projects
  • Pervious surfaces and paving types
  • vary in cost; research accordingly

Additional Resources and Definitions

5. Tree Plantingtree1

Tree Planting: DETAILED DESIGN GUIDELINES

BENEFITS

  • Trees add an aesthetic landscape feature and increase property values 
  • Screen unwanted views
  • Roots slows stormwater runoff; decreasing peak storm water flows
  • Add mulch and compost for added water retention
  • Trees provide oxygen and clean the air of pollutants
  • Trees prevent soil erosion
  • Trees can provide food
  • Trees provide a canopy and habitat for wildlife
  • Trees aid as a visual traffic calming measure

CONSIDERATIONS

  • Low maintenance once established
  • The larger the size of tree purchased (gallon or box size), the more expensive 
  • Be aware of overhead and underground utilities
  • Irrigation will be needed for plant establishment
  • Select an appropriate tree (sun/shade, wind exposure, soil type, California coastal native plants)

Additional Resources and Definitions

6. Gull Rooftop Deterrent StrategiesFor commercial properties in the Business District.
gull1

Gull Rooftop Deterrents: DETAILED DESIGN GUIDELINES

BENEFITS

  • Keeps nesting birds out of expensive rooftop equipment areas and HVAC units
  • Keeps rooftop clean from contaminants entering the storm drain
  • Reduce the need for rooftop cleaning
  • Eliminate smells
  • Decrease bird noise 

CONSIDERATIONS

  • Can be costly depending on the type
  • of bird deterrent chosen
  • Birds may adjust to the deterrent
  • type which means alternative deterrents may need to be reinstalled
  • Some deterrents will need to be
  • replaced over time depending on the deterrent. Regular monitoring is suggested

Additional Resources and Definitions

stay informed

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