Ecological Benchmarking Assessment for an Urbanized Estuarine River
description
Transcript of Ecological Benchmarking Assessment for an Urbanized Estuarine River
Ecological Benchmarking Assessment for an Urbanized Estuarine River
J.K. Shisler, T.J. Iannuzzi, A.D. Standbridge, J.M. Gonzalez, and D.F. Ludwig
2
3
What are Some Impacts to the Lower Passaic River (LPR)?
Shoreline features/impacts – lower 6 milesRight* Left*
Bulkhead 52.5% 51.9%
RipRap 32.3% 28.5%
Vegetation with RipRap 9.2% 13.8%
Aquatic Vegetation 6.0% 5.8%
*Facing Up-River from Newark Bay
4
Wetlands Loss in the Region
Mid-19th Century Today
5
Loss of Historic Tributaries in Region
River/Creek Estimated Length Lost (mi)
Bound Creek and Tributaries 18.1
Maple Island Creek and Tributaries 13.2
First River and Tributaries 6.0
Unnamed Passaic Tributary Creeks 0.7
Kearny Marsh Tributaries 1.2
Great Meadow Brook and Tributaries 6.3
Oyster Creek and Tributaries 2.3
Upper Newark Bay Tributaries 10.9
Other Newark Bay Tributaries 20.2
Total Lost 76.6
6
Can We Restore This System?
7
To What?
• It won’t look like this again• Many system constraints in an
urban river such as the LPR• Goal is to create an ecosystem
balanced for biological production, and human and wildlife use
• So, restoration requires:– Value judgments
– Ecological benchmarking
– Creative engineering
• Scope for restoration is substantial
8
Expected Natural Habitats
• Mudflat• Salt marsh – low marsh• Salt marsh – high marsh• Estuarine scrub-shrub• Transitional tidal marsh• Freshwater tidal marsh• Transitional and freshwater scrub-shrub• Floodplain forest
9
Objectives
• Examine existing habitats• Characterize and quantify physical and ecological
attributes or “benchmarks”• Use benchmarks as foundation for evaluating the likely
success of potential restoration projects
10
What is an ecological benchmark?
11
LPR Salinity Gradient
Salinity (ppth) River Mile
• Polyhaline 18 - 30 0.5
• Mesohaline 5 -18 5.1
• Oligohaline 0.5 - 5 6.8
• Freshwater >0.5 11.1
12
What Information Do We Need to Get Started?
• Know the constraints• Can we modify constraints to meet restoration goals?• Benchmark local reference wetlands
13
Limitations to Restoration in LPR
• Shoreline use/configuration• Geomorphic setting • Tidal zone • Flooding/inundation • Elevation• Salinity • Shade/sun • Substrate• Water velocity
14
Natural Salt Marsh is an Objective
15
Where is Spartina?
• Upper limit at about river
mile 2.7• Habitat conditions are a factor
16
Lower (i.e., Polyhaline) Section of LPR
17
RipRap Shoreline Edge
18
Old Bulkhead
19
Urban Tidal River
20
Can We Restore A Salt Marsh Habitat?
• The quick answer is yes, BUT• Location is critical• Will not have high marsh habitat since the area has been
lost due to development• Will be narrow bands with riprap as the ecotonal edge• Limited wildlife use• May require breakwater in front of the wetland
21
Local Wetland Restoration Effort - Why did it Fail?
• Located above elevation benchmarks for S. alterniflora in system
• Constraints from outside impacts– Geese– Floatables– Ice
• Requires extensive engineeringto overcome constraints
22
Where is the Brackish Water Tidal Wetland?
• Very limited locations within the LPR
23
Urban Impacts
24
Transitional-Freshwater Section Goal
25
Observed Habitat
Transitional-Freshwater Section of LPR
26
OBSERVED RIPARIAN HABITAT
Existing Transitional-Freshwater Habitat
27
Urban River Restoration Concepts and Conclusions
• Set realistic goals• Use benchmarking of
existing habitat attributes• Focus on function• Restoration vs. Creation• Adaptive Management
• Stakeholder Commitment
28
Questions?