Stream Restoration
The Evolution of Mitigation Practices to Achieve Better Restoration Endpoints •
Challenges to Stream Restoration Created by Mitigation Policy—Zack Mondry
•
Watershed Planning Adaptation in Response to a Shifting Regulatory Framework: an EEP Case Study—Rob Breeding
The Evolution of Mitigation Practices to Achieve Better Restoration Endpoints •
The Evolution of Stream Restoration in North Carolina: Beyond Dimension, Pattern, and Profile—John Hutton •
Beyond Mitigation Monitoring: Are These Projects Working?—Mac Haupt
Challenges to Stream Restoration Created by Mitigation Policy Zackary Mondry NCDENR Ecosystem Enhancement Program
March 28, 2012
Acknowledgments
Mac Haupt & Greg Melia--NCEEP Erin Bennett--NCSU Brian Lowther--NCDWQ
Outline: --2003 NC definition of stream restoration
--Typical NC stream restoration, enhancement
--Criteria for buffer restoration in NC --Examples if ineligible buffer
--Reassessing stream reference reaches --Geomorphic success criteria for streams
Stream Restoration: …process should be based on a reference condition/reach for the valley type and includes restoring the appropriate geomorphic dimension (cross-section), pattern (sinuosity), and profile (channel slopes)…
Restoration Site Construction
Enhancement Site Existing Conditions
Enhancement Level 1
9 Year Old Rootwad
Engineered Structure Assessment (2006) Distribution of Assessed Structures 13 sites surveyed, 500 structures evaluated
250 42%
Count
200 28%
150 100
10%
50
8%
8% 4%
0 Cross-Vanes
Root Wads/Wrap
Single-Arm Vanes
J-Hooks
Const. Riffles
Other
Engineered Structure Assessment (2006)
Count
Structure Overall Stability 450 400 350 300 250 200 150 100 50 0
74%
19%
100 - 75% Intact
75 - 50% Intact
4%
3%
50 - 25% Intact
25% Intact to Failed
Criteria for NC Riparian Buffer Restoration :
--Neuse, Tar-Pamlico, Catawba, Randleman, Jordan, Falls Lake
--Planted, native hardwoods --320 stems/acre at maturity
--50’ horizontal distance from top of bank
Ineligible Riparian Buffer Areas Along
Stream Restoration in Golf Course Development
Development
Ineligible Riparian Buffer Areas Along Stream Restoration in Golf Course Development
Ineligible Riparian Buffer Areas Along Stream Restoration in Golf Course Development
Reference Reach Assessment Hypothesis --We expect stream channels in alluvial
valleys to re-work and modify stream banks, even along reference reaches. --As such, constructed stream restoration projects should also be expected to have some bank re-working.
Reference Reach Assessment Methods --Visual assess. of 23 reaches in central NC
--Tally of scoured stream bank lengths --Noted dominant stream substrate, valley wall influence, bedrock control, large wood, canopy gaps, exotic invasives
Indicators of Active Bank Scour Along a Reference Reach
Indicators of Active Bank Scour in Along a Reference Reach
Indicators of Active Bank Scour in Along a Reference Reach
% Scoured Bank Length
Results of Reference Reach Assessment 25.0
20.0
15.0
10.0
5.0
0.0
Results Continued: --4.2 miles of stream assessed, 8.9% total bank length displayed active scour --Scour not predicted by drainage area or sinuosity --10% scour with large wood (7% without) --8% scour with canopy gaps (10% without)
Discussion: --Piedmont reference streams of various sizes display active bank scour --Scour occurs in the presence/absence of bedrock, large wood, and canopy gaps
--Constructed restorations likely should not be expected to perform better than forested,
bedrock-controlled reaches --Mitigation credit should not be reduced due to small areas of bank scour
Conclusion: --2003 Stream Guidelines need revision --Disincentive (ratios) for enhancement and preservation projects needs scrutiny --Consider credit for buffer < 50’ wide
--Streams evolve with changing water, sediment, and vegetation --Reframe concept of stability in terms of probable changes with positive/negative outcomes
Questions? Thank You For Your Interest! Zack Mondry 919-715-6933 [email protected]
Challenges to Stream Restoration Created by Mitigation Policy—Zack Mondry
•
Watershed Planning Adaptation in Response to a Shifting Regulatory Framework: an EEP Case Study—Rob Breeding
The Evolution of Mitigation Practices to Achieve Better Restoration Endpoints •
The Evolution of Stream Restoration in North Carolina: Beyond Dimension, Pattern, and Profile—John Hutton •
Beyond Mitigation Monitoring: Are These Projects Working?—Mac Haupt
Challenges to Stream Restoration Created by Mitigation Policy Zackary Mondry NCDENR Ecosystem Enhancement Program
March 28, 2012
Acknowledgments
Mac Haupt & Greg Melia--NCEEP Erin Bennett--NCSU Brian Lowther--NCDWQ
Outline: --2003 NC definition of stream restoration
--Typical NC stream restoration, enhancement
--Criteria for buffer restoration in NC --Examples if ineligible buffer
--Reassessing stream reference reaches --Geomorphic success criteria for streams
Stream Restoration: …process should be based on a reference condition/reach for the valley type and includes restoring the appropriate geomorphic dimension (cross-section), pattern (sinuosity), and profile (channel slopes)…
Restoration Site Construction
Enhancement Site Existing Conditions
Enhancement Level 1
9 Year Old Rootwad
Engineered Structure Assessment (2006) Distribution of Assessed Structures 13 sites surveyed, 500 structures evaluated
250 42%
Count
200 28%
150 100
10%
50
8%
8% 4%
0 Cross-Vanes
Root Wads/Wrap
Single-Arm Vanes
J-Hooks
Const. Riffles
Other
Engineered Structure Assessment (2006)
Count
Structure Overall Stability 450 400 350 300 250 200 150 100 50 0
74%
19%
100 - 75% Intact
75 - 50% Intact
4%
3%
50 - 25% Intact
25% Intact to Failed
Criteria for NC Riparian Buffer Restoration :
--Neuse, Tar-Pamlico, Catawba, Randleman, Jordan, Falls Lake
--Planted, native hardwoods --320 stems/acre at maturity
--50’ horizontal distance from top of bank
Ineligible Riparian Buffer Areas Along
Stream Restoration in Golf Course Development
Development
Ineligible Riparian Buffer Areas Along Stream Restoration in Golf Course Development
Ineligible Riparian Buffer Areas Along Stream Restoration in Golf Course Development
Reference Reach Assessment Hypothesis --We expect stream channels in alluvial
valleys to re-work and modify stream banks, even along reference reaches. --As such, constructed stream restoration projects should also be expected to have some bank re-working.
Reference Reach Assessment Methods --Visual assess. of 23 reaches in central NC
--Tally of scoured stream bank lengths --Noted dominant stream substrate, valley wall influence, bedrock control, large wood, canopy gaps, exotic invasives
Indicators of Active Bank Scour Along a Reference Reach
Indicators of Active Bank Scour in Along a Reference Reach
Indicators of Active Bank Scour in Along a Reference Reach
% Scoured Bank Length
Results of Reference Reach Assessment 25.0
20.0
15.0
10.0
5.0
0.0
Results Continued: --4.2 miles of stream assessed, 8.9% total bank length displayed active scour --Scour not predicted by drainage area or sinuosity --10% scour with large wood (7% without) --8% scour with canopy gaps (10% without)
Discussion: --Piedmont reference streams of various sizes display active bank scour --Scour occurs in the presence/absence of bedrock, large wood, and canopy gaps
--Constructed restorations likely should not be expected to perform better than forested,
bedrock-controlled reaches --Mitigation credit should not be reduced due to small areas of bank scour
Conclusion: --2003 Stream Guidelines need revision --Disincentive (ratios) for enhancement and preservation projects needs scrutiny --Consider credit for buffer < 50’ wide
--Streams evolve with changing water, sediment, and vegetation --Reframe concept of stability in terms of probable changes with positive/negative outcomes
Questions? Thank You For Your Interest! Zack Mondry 919-715-6933 [email protected]
