Donaldson Run Tributary B Stream Restoration Project Update February 23, 2011 Taylor Elementary School
Big picture concepts Past land use and drainage decisions have severely impacted County streams Watershed improvements and in-stream restoration efforts are both essential Urban stream corridor damage must be addressed comprehensively Stream restoration accomplishes multiple resource management objectives Neighborhood partnership is essential
County/Donaldson Run Civic Association Partnership 10+ year partnership Stream restoration top neighborhood priority NCAC approved Tributary B funding in December 2007; County Board 2008; DES providing additional funds Extensive County/DRCA public process: meetings, workshops, stream walks, newsletter articles, park signs, Citizen articles, and other media coverage
Donaldson Run watershed Donaldson Run Watershed Boundary Tributary C Tributary B Taylor School Tributary A
KEY PROJECT FACTS: Approved Neighborhood Conservation Program Project 1,400 linear feet to Upton street 26% impervious cover in watershed Natural channel design approach
Review of changes from 30% to 60% design Reducing width of channel/floodplain to reduce footprint and tree/valley impacts Limiting re-location of pathway and narrowing pathway Reducing disturbance and tree impacts below the footbridge
Updates from 60% design to current design level (~75%) Step pool grade control and riffle structures Analysis of hillside and storm pipe drainage inputs Water main survey Planting plan Invasive plant management
Step Pool Grade Control and Control stream energy Protect streambanks Provide improved stream habitat Riffle Structures
Hillside drainage inputs Working with specific property owners Accommodating flow inputs in project design
Storm pipe drainage inputs Verifying easements/pipe conditions Incorporating needed repairs/modifications into project design
30 Water Main Primary Source of Supply to Lee Water Station Long-exposed pipe segments in valley identified as 30 water main and surveyed to determine location Interim work completed to protect exposed pipe Few apparent conflicts with stream restoration design except at stilling basin Small borings will be excavated to confirm pipe elevations Stream restoration design will improve protection
Trees No change in tree impacts from project from 60% designs to current design One tree removed to protect water main (previously listed as a potential removal) One tree has fallen (previously listed as a removal) Project impact: 36 trees>10 diameter, 72 trees overall
Invasive Management & Planting Plan Goals: To restore forest structure and function To support recreational use and aesthetics
Invasive Management & Planting Plan Why invasive management? Displace native species Reduce wildlife habitat Alter ecosystem processes On a global basis...the two great destroyers of biodiversity are, first habitat destruction, and, second invasion by exotic species. E. O. Wilson Courtesy NPS Japanese Barberry Japanese (Berberis stiltgrass thunbergii) (Microstegium vimineum)
Current Forest Conditions
Resources Natural Resource Management Plan http://www.arlingtonva.us/departments/parksrecreation/docu ments/file76445.pdf Ecological community mapping Modified urban landscape Species inventory for Zachary Taylor Park Keeping it Natural http://www.arlingtonva.us/departments/environmentalservic es/epo/pdffiles/keeping%20it%20natural.pdf
Wisteria
Kudzu Invasive Plants 85-95% invasive species in the shrub and ground layers invasive species present on both park and private properties 27 different species
Implications Invasive management considerable component of the project Project requires integrated planting and invasive plant removal 4-6 year planting and invasive plant maintenance schedule Complete removal of invasive species is likely not possible Most successful if private citizens are involved in invasive management
Planting Plan Site specific All plants will be native to Zachary Taylor Park Planting zones to account for habitat changes with elevation and distance from the stream. Special plantings for sensitive areas Multi-year to account for invasive control and natural forest succession
Zoned Planting - Example Slope Floodplain
Special Areas Stream Banks
Special Areas Bare Slopes
Scarlet oak Quercus coccinea Arrowwood Viburnum dentatum Bluestem goldenrod Solidago caesia
Pre-project Invasive Management removal of invasive shrubs outreach to homeowners During construction/planting Clean equipment Mulch or mats for trees/shrubs Seed heavily Protect deer candy Multiple planting cycles
Invasive Management Post-Project/Maintenance Protect trees and shrubs Focus on stream banks Target species Coordinate invasive removal and planting Timing of control will depend on plant life cycle Flexible and adaptive
English Ivy (Hedera helix)
Next Steps Continue work with property owners on hillside drainage inputs and design work for storm pipe drainage inputs Finalize planting plan and invasive plant management plan Develop construction access/staging plan Hold stakeholder advisory group meeting prior to full design completion Target design completion by end of summer Construction schedule still TBD
Tributary A, June 2010 For more information contact: Jason Papacosma / Christin Jolicoeur Arlington County Dept. of Environmental Services Environmental Management Bureau (703) 228-3613 jpapacosma@arlingtonva.us cjolicoeur@arlingtonva.us Learn more at: www.arlingtonva.us search Donaldson Run.