Arlington County 5/10/19 Engineer’s Estimate of Donaldson Run Restoration costs and funds spent through 12/2/19.
According to the budget Trib B – Project #S32D as of 12-2-19 had spent $181,277 with “encumbrances” of $9,870. The 5-10-19 engineer’s estimate for stream work only was $1.445 M and does not include infrastructure repair or replacement. For the 1331 linear feet of the project, this is $1086 per foot before any related expenses. Details.
Preserving mature trees should be the top priority for the health of the public and environment this analysis shows.
The facts show that preserving trees should be the first priority for the immediate health of the public and environment. There is no doubt that planting trees for the future 20 to 50 years from now is also essential. The two are complimentary but both are crucial .
A single 2″ tree replanted has very limited storm water, environmental, and
financial value compared to a 31″ tree of the same species today. This is to be expected. The quantitative comparison shows that the 31″ tree intercepts 11,748 gallons of storm water while the 2″ tree only intercepts 51 gallons.
After 20 years, it would still require ten 10″ trees to equal the storm water benefits of the 31″ today (assuming the 31″ does not grow anymore). It is estimated that it will be 72 years before the 2″ tree grows to 31″.
Concerns for the Potential Costs and Damage from stream “restoration” in Arlington
For over a decade, the previously restored Tributary A of Donaldson Run has had mixed success. This pictorial overview of the problems encountered after construction offer lessons to be learned that should be applied to future restorations.
Problems with Stream Restoration in General and in Donaldson Run:
River restoration: the fuzzy logic of repairing reaches to reverse catchment scale degradation.
Bernhardt and Palmer say: “New efforts to evaluate river restoration projects that use channel reconfiguration as a methodology for improving stream ecosystem structure and function are finding little evidence for measurable ecological improvement. While designed channels may have less‐incised banks and greater sinuosity than the degraded streams they replace, these reach‐scale efforts do not appear to be effectively mitigating the physical, hydrological, or chemical alterations that are responsible for the loss of sensitive taxa and the declines in water quality that typically motivate restoration efforts.”
The Ecological Restorations Industry – Follow the Money
Expensive Stream Restoration Failures Will Diminish Our Nation’s Appetite for Restoration
Restoring Streams in an Urbanizing World
See “Channel Reconfiguration and Grade Control“, p.8 and “Restoration and effective catchment management”, p10
River restoration: the fuzzy logic of repairing reaches to reverse catchment scale degradation
Bulldozing a creek in order to help save it
The Efficacy of Constructed Stream−Wetland Complexes at Reducing the Flux of Suspended Solids to Chesapeake Bay
Stream Restoration & Invasives
“The Limits of Restoration: Getting to Know the True Nature of Your Stream Valley and Hopefully Keeping It Intact!” (Rod Simmons, Natural Resource Manager, City of Alexandria Dept. Recreation, Parks, and Cultural Activities, Natural Resources Division), 2017. http://www.accotink.org/2016/StreamRestorationLimits.pdf.
Arlington’s Tree Canopy
Arlington County i-Tree Ecosystem Analysis
Arlington County Tree Canopy Gain/Loss 2008-2011 (Note: no update has been done.)
Invasive Species Preoccupation:
Are Critics of Invasion Biology Pessimists or Realists?
Environmental Dangers to Forests:
The Forest is Greater Than the Sum of Its Parts