Remediation of Impacts to Wetlands

Transcription

1 Remediation of Impacts to Wetlands 1

2 Mitigation Strategies Avoidance Minimization Compensation 2

3 Minimization of Wetland Impacts 3

4 Steps in Compensatory Mitigation Define Objective Regulatory Agencies Evaluation of Impacts Regional Need Amenity of Development Functional Need of Development Choice of Applicant Describe General Characteristics of Mitigation Type Hydrology Vegetation Site Selection Feasibility Costs Constraints/Opportunities 4

5 Wetland Mitigation Site Selection Criteria Feasibility Costs Constraints/Opportunities Site Selection Process Off-Site On-Site Modify Plans to Suit Site 5

6 Site Selection Information 6

7 Flow Chart of Compensatory Mitigation 7

8 Forms of Compensatory Mitigation Restoration Enhancement Creation Banking Payment In-lieu of 8

9 Restoration Restoring wetland function to an area that was previously a wetland and has been altered by change: Hydrology Vegetation Filling 9

10 Restoring Altered Hydrology 10

11 Restoring Altered Hydrology 11

12 Restoring Altered Elevation Before Excavation After Excavation Completed 12

13 Enhancement of Functions Enhancing a marginally functional wetland to perform specific functions 13

14 Enhancing Habitat Functions Before Enhancement After Enhancement 14

15 Enhancing Bank Stabilization 15

16 Creation Creating a wetland area where none existing before 16

17 Eagle Run Mitigation - Original Conditions 17

18 Eagle Run Mitigation - Grading Plans 18

19 Eagle Run Mitigation - Excavation 19

20 Eagle Run Mitigation - Tidal Swale 20

21 Eagle Run Mitigation - Gabion Weir 21

22 Eagle Run Mitigation - Low Tide 22

23 Tidal Conditions High Tide Low Tide 23

24 Costco - Grading Plan 24

25 Costco - Planting Plan 25

26 Construction of Compensatory Mitigation Timing Early spring Late Fall Activities Land Preparation Clearing/Grubbing Excavation Grading Compacting Liner Top Soil Final Grading Planting Ground Cover Specified Plants 26

27 Operation and Maintenance Irrigation First Season Spring inundate 1-2 inches for 5-7 days Mid-Summer inundate 5 inches for 3-5 days, then increase to 10 inches 3-5 days Second Season Spring inundate transition area at first warm spell, lower when warm weather is set in for 5-10 days Inundate 1 inches for 5-10 days 27

28 Operation and Maintenance (cont.) Control of Nuisance Plants Herbicide Mowing Long-Term Periodic Draw-down Controlled burning Fencing 28

29 Wetland Mitigation Banking Concept Wetland Acreage Savings Account of Created Wetlands Withdrawal for Mitigation Credit Advantages Implementing and functional before impact Large areas better than several small areas Usually designed by experts with incentive to perform Bring together financial resources of many Reduce uncertainty of regulatory agencies Easier for Regulatory Agencies to track Disadvantages If it fails there is a large loss Sponsors take large risk with no guarantee Issues In-kind In Watershed Agency Agreements 29

30 Oregon Wetland Banking Oregon Wetland Mitigation Bank Act 1987 Bank only used when on-site is not practicable or where off-site is environmentally preferable Requirements to Establish a Bank: Meet with DSL Submit Prospectus Develop Instrument Location Need Existing Condition of Site/Adjacent Areas List of Adjacent Property Owners Ecological Goals Wetland Functions Site Plan (including buffers) Monitoring Plan Contingency Plan (flood/invasive vegetation/eat- out/etc.) Local Approval Plans for Long-term Management 30

31 Oregon Wetland Banking (cont.) DSL Review Mitigation Bank Review Team (ACOE/DSL/Others) Review Prospectus Participate in Development of Instrument Review Performance (at least annually) DSL Approval Credits Depend on Method of Mitigation Development Remaining Credits Can Increase Buffers Can Earn Credits after 5 Years 31

32 32

33 Wetland Mitigation by Payment- In-Lieu This mitigation option allows payment tied to the cost to replace the functions of the affected wetland, generally based on construction costs The payment is made to the Division of State Lands for their discretionary use in wetland projects This option is only allowed for small impacts (0.2 acres), or by special authorization of the Director of the Division of State Lands Payment determined as monetary value of the lost/affected wetlands, usually by a formula based on construction costs, and reserving the money in the contract 33

34 Ranked Preference for Mitigation Options In-Basin Mitigation Bank (3/31/08) On-site, in-kind On-site, out-of of-kind Off-site, in-kind (in-basin) Off-site, out-of of-kind (In-basin) In-Basin Payment-to to-provide Payment-in in-lieu 34

35 Purpose of Evaluation Regulatory Correction Functions to Evaluate Groundwater Flood Storage Shoreline Stabilization Sediment Trapping Water Quality Food Chain Support Wildlife Habitat Aquatic Habitat Recreation Monitoring 35

36 Government Island Monitoring 36

37 Effectiveness of Wetland Mitigation National Research Council 2001 Net Loss in Wetland Area Net Loss in Wetland Function Mitigation Success Highly successful Highly unsuccessful 37

38 Factors Contributing to Lack of Success No irrigation of planted materials Poor site selection Lack of maintenance Poor mitigation design Lack of hydrologic monitoring prior to construction Lack of follow-up by Regulatory Agencies Compacted soils A buffer too small or unvegetated Lack of consistency between goals and plan Lack of experience Johnson et al

39 Factors Contributing to Success Adequate source of hydrology Same consultant Good site selection Oversight and follow-up by Regulatory Agencies Designer on-site during construction Good mitigation design Native seed source present Maintenance conducted on site Irrigation for at least 1 growing season Hydrologic monitoring prior to construction Johnson et al

40 National Compensatory Mitigation Action Plan General Regulatory Guidance Integrating Mitigation into Watershed On Site/Off Site & In-kind/Out of Kind guidance Vegetated Buffer Guidance Preservation Guidance Watershed Context Guidance Improving Accountability Banking Guidance Grants to Improve Mitigation Guidance for Difficult To Replace Areas Stream Mitigation 40

41 National Compensatory Mitigation Action Plan (cont.) Clarifying Performance Standards Model Mitigation Checklist Adapt NAS-guidelines to 404 Program Analysis of Existing Standards Clarify Performance Standard Concepts Performance Standard Guidance Improving Data Collection Evaluate Existing Mitigation Databases Develop Common Mitigation Databases Annual Report Card 41