LID Techniques & Design Guidelines 

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 Redirection

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.



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)  

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.


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 Planting

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.


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