Stormwater management criteria

Stormwater Management Stormwater Management CriteriaCriteria

By: Johnny Foster

IntroductionIntroduction

Vegetation ManagementFisheries ManagementNuisance Animals ManagementStructures Management

Vegetation ManagementVegetation Management

No trees on damWell established grassProper grass maintenanceDo not allow woody growth to obstruct

water flowAquatic vegetation must be managed

Do not allow trees to become Do not allow trees to become established on the dam.established on the dam.

Roots can cause leaksDislodged root balls

weaken damsShade reduces vigor of

grass holding the soil Cut trees less than 6

inch diameterExcavate trees larger

than 6 inch diameter

Vegetation Management

Make sure grass is Make sure grass is established around entire established around entire

pond, especially dam top and pond, especially dam top and slopes. slopes.

Dense grass controls erosion. Erosion removes topsoil and

contributes sediment to the pond. Till, lime, fertilize, seed, mulch

and irrigate bare spots. Control geese while grass is being

established.

Vegetation Management

Generally maintain grass height Generally maintain grass height at 2 to 6 inchesat 2 to 6 inches

Proper mowing promotes vigor.

Inspection is easier and more effective.

Don’t fertilize except during establishment.

Narrow fringe of taller grass may deter geese.

Vegetation Management

Keep inlet/outlet pipes, rip rap Keep inlet/outlet pipes, rip rap channels, plunge pools and channels, plunge pools and

discharge areas free of woody discharge areas free of woody brush and trees.brush and trees.

Water flow may be restricted.

Eroded gullies may form around obstructions.

Growth may damage underlayment fabric beneath stone.

Vegetation Management

Aquatic vegetation must be Aquatic vegetation must be managed. managed.

Native diverse shoreline vegetation can be desirable.

Filamentous algae, invasive species and aggressive spreading shoreline plants should be controlled.

Duckweed and watermeal can contribute to fish kills.

Vegetation Management

Fisheries ManagementFisheries Management

Fish stocking strategies depend upon property owners’ objectives.

Low maintenance, no fishing strategyLow maintenance, some fishing strategyModerate maintenance, productive

recreational fishing strategy

Low maintenance, no fishing Low maintenance, no fishing allowed strategy allowed strategy

Mosquitofish (Gambusia) often establish naturally

Some type of minnow necessary to control mosquitoes

Sterile grass carp are often the least expensive long-term control method for many types of nuisance aquatic vegetation

Don’t allow anyone to release live fish

Fisheries Management

Low maintenance, some fishing Low maintenance, some fishing allowed strategyallowed strategy

Stock channel catfish at 50 per surface acre. They will usually not reproduce.

Stock fathead minnows at 5 pounds per acre. Restock when no minnows are obvious around shoreline.

Stock sterile grass carp at 20 fish per VEGETATED acre

Don’t allow anyone to release live fish

Fisheries Management

Moderate maintenance, productive Moderate maintenance, productive recreational fishing strategy recreational fishing strategy

Stock 50 largemouth bass per surface acre

Stock 500 bluegill (bream) per surface are

Stock 50 channel catfish per surface acre

Stock 5 pounds of fathead minnows per acre

Stock 20 sterile grass carp per VEGETATED surface acre

Fisheries Management

We suggest you discourage We suggest you discourage people from eating fish from people from eating fish from ponds receiving significant ponds receiving significant stormwater runoff. You just stormwater runoff. You just never know what may have never know what may have

washed into the pond. washed into the pond.

Fisheries Management

Nuisance Animal Nuisance Animal ManagementManagement

BeaversMuskratsGeese Snakes

Beavers Beavers Large dens in banks

may weaken dam and contribute to erosion

Sticks, mud and debris can clog drains, spillways and pipes

May damage desirable and planted ornamental trees

May leave sign while just “passing through”

Nuisance Animal Management

Muskrats Muskrats May reproduce rapidly Holes, dens and runs

contribute to shoreline erosion

Dens may lead to failure of the dam

May eat desirable plants just planted

May eat desirable plants established naturally

Nuisance Animal Management

Geese Geese Only resident populations

create a nuisance May prevent desirable

grass establishment Feces contribute to

nutrient loading in pond Feces and feathers are

messy May be extremely

difficult to control

Nuisance Animal Management

Snakes Snakes Rarely poisonous but still

scary to residents Often like to hang out

around rip rap stone Rarely a problem with

regular maintenance of shoreline and structures

Nuisance Animal Management

Pond Structures ManagementPond Structures Management Dam Primary drain Emergency spillway Energy dissipater Emergency spillway Valve Inlet/outlet pipes and channels Forebay & forebay berm Vegetative shelf Fences

Dam Dam Seepage at

downstream toe or abutment

Shoreline erosionSloughing or sink

holesVegetation

managementAnimal damage

Pond Structures Management

Primary Drain Primary Drain Clear any trash or debris

monthly or after 1 inch of rain

Check condition of trash rackLook for corrosion, chipping,

pipe separation, cracks, erosion at discharge

Look for seepage into or along drain

Pond Structures Management

Emergency Spillway Emergency Spillway Repair erosion, gullies or any

type of damage Repair turf matting or exposed

underlayment fabric Repair dislodged or displaced

stone Should have wide flat bottom Should have gentle slope

Pond Structures Management

Energy dissipater Energy dissipater Repair erosion or damageRemove sediment depositsRemove woody vegetationRepair dislodged or

displaced stoneAdd stone on exposed

underlayment fabric

Pond Structures Management

Drain valve Drain valve Should be operable and

excercisedRepair damaged supportsClear upstream debris or

sediment before openingKeep lubricatedMaintain the lock

Pond Structures Management

Inlet/Outlet Pipes and Channels Inlet/Outlet Pipes and Channels Repair corrosion, chipping,

pipe separation, cracks, collapse or adjacent erosion

Remove sediment depositsRemove woody vegetationRepair displaced stone or

exposed fabricRepair damaged turf matting

Pond Structures Management

Forebay and Forebay Berm Forebay and Forebay Berm Remove sediment depositsManage vegetationRepair erosionRepair animal damageMaintain berm height and

spillway designReplace displaced stone on

berm

Pond Structures Management

Vegetative Shelf Vegetative Shelf Repair erosionManage vegetationRemove trash and debrisRepair animal damageMaintain design width

and slope

Pond Structures Management

Fences Fences Repair damageMaintain gate and lockRemove damaging

woody vegetationRepair animal damage

and gaps at bottom

Pond Structures Management

Where Can You Get More Where Can You Get More Information?Information?

Center for Aquatic and Invasive Plants (http://plants.ifas.ufl.edu/)

N.C. State University Stormwater Engineering Group (www.bae.ncsu.edu/stormwater/)

North American Lake Management Society (www.nalms.org)

Aquatic Plant Management Society (www.apms.org)

QUESTIONS?QUESTIONS?