vernal pools - mad scientist 2 09

Specialists in Ecological & Wetland

Consulting

www.madscientistassociates.netOEC 2009 Vernal Pool Workshop

MAD Scientist & Associates LLC

Established in 1998

Mark A. Dilley Chris S. DilleyFounder and Co-OwnerCo-Owner

www.madscientistassociates.net

MAD Scientist & Associates LLC

Technical StaffMark A. Dilley, M.S., P.W.S.• Professional Wetland Scientist• Certified Ecologist• B.S. in Natural Resources, OSU• M.S. in Environmental Science, OSU

J. David Strong• Environmental Scientist

Kashmira Asnani, M.S.• Ecologist


Vernal Pool Construction


Alternate Title:

Mark vs. the Pizza!!

What Makes A Wetland?3 Parameters:

Hydrophytic vegetation• Obligate wetland (OBL)• Facultative (FACW, FAC, FACU)• Obligate upland (UPL)

Hydric soils• Low chroma• Mottles

Wetland hydrology• Inundation• Saturation• Other indicators

May be sparse in

some vernal pools!

Wetland Hydrologywww.madscientistassociates.net

Hydric Soil

Site Selection“Location, Location, Location!”•Avoid existing wetlands!•Consider the neighbors (mosquitoes and flooding may not be appreciated!)•Avoid areas with livestock•Adjacent upland habitat and nearby wetlands are a plus (many would argue a necessity!)


Site Selection(continued)


•Consider (and adjust for) factors that will influence hydrologic regime (frequency and duration of flooding), including sunlight exposure, soil permeability, annual precipitation and evaporation, transpiration, and water depth.•Be cautious with sites that have a high water table!

Topography/Landscape Position

•Look for areas where water would naturally collect (floodplains, valleys)•Flat areas (<3% slope) make for easier/less expensive pool development•Embankment pools on hillsides are possible


Soils•Drained hydric soils are ideal•Silt loams, silty clay loams (fine textured soils) are generally suited to pool construction (permeability rates <0.2 in/hr; can check with simple equipment)•Drainage class of somewhat poorly drained to poorly drained •Liners, while not recommended, can be used in areas that drain too rapidly ($$$)


Sizing•Gaps in forest community as small as15’ x 15’ can suffice (tree removal is generally discouraged)•Vernal pools do not require a large watershed, due to the low storage volume•Typical sizes range from several hundred square feet to 3 or more acres


Site Preparation

•Invasive species removal•Trash clean up•Mark areas, trees to avoid•Determine, clear and mark route of ingress and egress•Mark pool, berm, and soil disposal locations


Earthwork•Remove and stockpile topsoil (seedbank and rooting medium)•Excavate shallow depression (1’-2’; use laser-guided equipment if possible; go deeper to allow for addition of topsoil)•If constructing a berm, dig, fill and compact core trench before building berm (in layers) on top •Use gentle slopes (15:1 or greater) •Install spillway (and control structure, if desired)


Earthwork(continued)

•Spread topsoil across wetland•Mini-excavator and small bulldozer will typically suffice•Look for competent operators

TNT can make vernal pool construction a blast!!!


Planting

•Seed and mulch (include cover crop)•Plugs = instant wetland plants!•Container grown trees and shrubs •For a variety of reasons, you may wish to avoid planting woody species on berms•Don’t forget the buffer!


Accessorizing•Add structure in the form of logs, rocks, leaf litter, small high spots of soil, and “specimen” plants•Do not let anyone convince you that tires are vernal pool accessories!


Example Projects and Lessons Learned

Heritage Park Phase II

Boyer Nature Preserve Vernal Pool Mitigation Area


Heritage Park Phase II, Westerville, OH

Vernal Poolwww.madscientistassociates.net

Gray Treefrog (Hyla chrysoscelis or H. versicolor)

On-site Mitigation Wetland #1Soon After Construction


On-site Mitigation Wetland #1First Year - 2003


Lesson Learned: Seed banks work!!

On-site Mitigation Wetland #1First Year - 2003


N. Leopard Frog (Rana pipiens)American Toad (Bufo americanus americanus)

Spring 2004 – AmphibiansHeritage Park Mitigation Wetlands


Lesson Learned: Build it and they will come!

Boyer Nature Preserve

Mitigation Opportunity

• Concerns of long-term neighbors regarding loss of spring peepers• Probably a loss of habitat issue• City was advised to look for opportunities to

create vernal pools as replacement habitat

• FACT promoted local mitigation at this preserve to off-set impacts within the local watershed

Draft Master Plan

The Vernal Pool Site

Covered in Amur honeysuckle

PreparationWetland delineationInvasive species removal (FACT volunteers and others)

Site Preparation

Vernal Pool Excavation

Seeding and Planting

Lesson Learned: Plugs are a reliable way to jump-start the plant community

Adaptive ManagementIssues

Lesson Learned: Properly size culverts or avoid altogether

Three Years Later…

Young American Toad

No spring peepers – yet!

Some satisfied vernal pool customers!!

Resources

•See handout for recommended books

•MAD Scientist & Associates


THANK YOU!

Questions?

vernal pools - mad scientist 2 09

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