Wetland and Stream Functional Assessment in North Carolina- A New Regulatory World?

Transcription

1 Wetland and Stream Functional Assessment in North Carolina- A New Regulatory World? John R. Dorney Moffatt & Nichol, Raleigh, NC September 14, 2015 North Carolina APWA Stormwater Conference, Wilmington, NC 1

2 Overview of Presentation Overall goal general understanding of NC WAM and NC SAM. Review past data on NC WAM Watershed planning, Permitting, and Mitigation. Review potential use of NC WAM to determine functional uplift from wetland enhancement. 2

3 Use of NC WAM and NC SAM in NC Wilmington District - Public Notice April 21, 2015 Implementation of the North Carolina Stream Assessment Method and North Carolina Wetland Assessment Method 3

4 Use of NC WAM and NC SAM in NC (cont.) The District will begin to utilize NC WAM and NC SAM for our internal reviews of permit applications, including decisions regarding the amount and type of compensatory mitigation, avoidance and minimization of impacts, or other decisions pertaining to aquatic resource quality and functions. 4

5 Use of NC WAM and NC SAM in NC (cont.) The results of NC WAM and NC SAM may now be considered by the District, along with other factors, to adjust the typical 2 to 1 mitigation ratio in order to account for high or low quality aquatic resources 5

6 Basin Wetland Croatoan National Forest 6

7 Stream Piedmont,Size - Piedmont, Size 2, a 2, a valley valley Wake County 7

8 Background Presently, state agencies and Corps regulate stream and wetland fill by length (feet) and area (acres), respectively. Interest in EPA, and Corps of Engineers administration to also regulate based on wetland and stream value (quality). Strong support in existing Corps, DENR, and EPA rules for this approach. 8

9 What are NC WAM and NC SAM? Methods which rapidly (15 minutes) assess the quality of wetlands and streams. Developed by inter-agency teams of state and federal staff from Visited total of 560 sites across the state of varying quality. Total of 1,400 person hours in office and field. 9

10 Important considerations with NC WAM/ NC SAM Rapid method defined as taking no more than 15 minutes per site after training and after delineation. Reference based. Compare site to its appropriate suite of reference sites. Does not replace Best Professional Judgment. Can override NC WAM/NC SAM but need written explanation. Ultimately regulator decides.

11 What is NC WAM? General considerations High, Medium and Low values by separate function and overall. 16 General Wetland Types. Comparisons within wetland stream type. Comparisons between wetland type regulatory agency decision. Stressors important consideration. NC WAM is not a delineation method delineation must be done first using 1987 Manual and appropriate supplements. 11

12 Three Main Functions Hydrology. Water Quality. Habitat. 12

13 Hydrology Function Surface storage and retention. Sub-surface storage and retention. 13

14 Water Storage Floodplain Pool White Pines Natural Area, Lee County 14

15 Water Quality Function Particulate change. Soluble change. Pathogen change. Physical change. Pollution change. 15

16 Habitat Function Habitat physical structure. Landscape patch structure. Connectivity. Vegetation composition. 16

17 17

18 Riverine Swamp Forest Goose Creek State Park 18

19 NC WAM Field Assessment Form 19

20 What is NC SAM? General considerations High, Medium and Low values by separate function and overall. 29 Stream Types Four physiographic regions. Two valley types Five watershed sizes. Tidal. Intermittent versus perennial. Stressors important consideration. NC SAM is not a delineation method. 20

21 Three Main Functions Hydrology. Water Quality. Habitat. 21

22 Hydrology Function Baseflow. Floodflow. Stream/Intertidal Zone Interaction. Longitudinal Tidal Flow. Tidal Marsh Stability. 22

23 Water Quality Function Baseflow. Streamside area vegetation. Stressors. Aquatic life tolerance. Intertidal zone filtration. 23

24 Water quality stressor excessive sediment Mountain, size 4, a valley Jackson County 24

25 Habitat Function In-stream habitat. Streamside habitat. Tidal marsh in-stream habitat. Intertidal zone. 25

26 Leaf pack in a riffle Inner coastal plain, size 1, a valley Cumberland County 26

27 NC SAM Field Assessment Form 27

28 Tidal Marsh Stream Beaufort County 28

29 Overall Evaluation Process- NC WAM and NC SAM One Field Assessment Form per method (four pages each) with all metrics. Form completed in field with some office map work. Evaluate with Rating Calculator (computer program). Rating Calculator reflects Team s relative weighting of each metric via Boolean logic. Boolean logic is a systematic combination of evaluated metrics, sub-functions, and functions. Generates rating of High, Medium, or Low for each sub-functions, three functions, and then one overall rating. 29

30 Final Phase Replaced DWQ Wetland Rating System eventually replace Corps Stream Assessment Form. First round of training for agency staff fall and winter 2008 for NC WAM. In 2013 for NC SAM. Focused on agency training Fourteen NC WAM class taught to date. Four NC SAM classes taught to date. Training for private sector to be offered in

31 Implementation Approach NC WAM/NC SAM are the tools. Next question, how to use them? Decision by regulatory agencies not Wetland Functional Assessment Team. Implementation Team began meeting in 2008 DWQ, Corps, EPA, and DCM. Guidance released by Corps in April

32 Implementation Approach (cont.) In general, NC WAM / NC SAM can be used for: Environmental documentation. Avoidance and minimization for permitting. Compliance and enforcement. Watershed assessments. Training. Mitigation. 32

33 Implementation Approach (cont.) In general, impacts to lower quality wetlands/streams will require less mitigation. Impacts to higher quality wetlands/streams will require more mitigation. Essentially, we can replace functions in addition to acres for wetlands/streams. For instance, this method will allow us to count functional uplift from wetland enhancement towards 1:1 replacement (i.e., no net loss of function). 33

34 Uses of NC WAM Examples Various potential uses Wetland Inventories. Watershed Planning. Wetland Permitting. Functional Uplift from Enhancement. 34

35 Wetland Condition Surveys Isolated Wetland Study in Eight County study area NC and SC. Prepare GIS wetland map Mainly based on LiDAR data Field check GIS map for accuracy. Conduct NC WAM evaluations on isolated wetland sites at 180 randomly selected sites. 35

36 Study area 36

37 Overall Results Function High Medium Low Overall Quality 67% 30% 3% Hydrology Function Water Quality Function 67% 30% 3% 51% 37% 12% Habitat Function 70% 16% 14% 37

38 Indian- Howard Creek Watershed Plan Inventory of wetland condition for watershed plan for NC Ecosystem Enhancement Program. Work done with Susan Gale while at NC DWQ. Pilot work on two piedmont watersheds in NC. Indian and Howard Creeks, Lincoln County. 38

39 Local Watershed Planning Purpose characterize watershed so compensatory mitigation can address watershed needs. Monitoring water chemistry, aquatic macrobenthos, physical attributes. Modeling watershed level by consultants. Wetland data very sparse. All done in conjunction with state s in lieu fee program (Ecosystem Enhancement Program). 39

40 Bottomland Hardwood Forest 40

41 Indian Howard Creek results Visited 67 sites. Found 33 wetlands. Average size 1.3 acres. Median size 0.5 acres. Range 0.01 to 13.9 acres. NC WAM scores High 64% (21 sites), Medium 12% (4 sites), Low 24% (8 sites). 41

42 Summary NC WAM/NC SAM appear to be useful for rapid characterization of wetland and stream condition in a watershed. NC WAM results can be used for larger wetlands to target mitigation sites especially for functional uplift from wetland enhancement. 42

43 Wetland Permitting Use to characterize wetland function for projects. Orton Plantation, proposed refurbished rice plantation, Wilmington, North Carolina. 43

44 Orton Plantation, Wilmington, NC Propose renovation/ reestablishment of rice cultivation at Orton Plantation on Cape Fear River. Used NC WAM to characterize quality of existing wetlands. Minimization of impact. Eventual permit to impact 287 acres of mostly low value wetlands. Used NC WAM to determine which wetland functions impacted and which to mitigate. 44

45 Summary of NC WAM results 45

46 Functional uplift using NC WAM Meadow Branch site along SaddleTree Swamp in Robeson County (southeastern coastal plain). Intact riverine swamp forest and bottomland hardwood forest. Saddletree Swamp has been ditched with spoil berm parallel to stream (4 to 6 feet high). Very common situation in NC coastal plain. Also old logging road with fill on site. 46

47 Functional Uplift Determination Current state rules require 1:1 restoration or creation for mitigation to achieve no net loss. Possible to use NC WAM to calculate functional uplift from enhancement and count net gain of function toward no net loss. Calculate overall wetland function. Current condition versus enhanced condition. Determine acreage increase in function. 47

48 Meadow Branch site plan 48

49 Proposed method to calculate functional uplift Overall, compare present condition of wetland to future condition after enhancement to calculate functional uplift. Use NC WAM to calculate existing condition and to project future condition where overall function of High = 3, Medium = 2 and Low = 1. 49

50 Proposed method to calculate functional uplift - equation Functional uplift EnhAcres MitQual post EnhTypeRatio EnhQual pre Equation terms : EnhAcres = Enhancement acreage MitQual post = Mitigation quality post enhancement MitQual pre = Mitigation quality pre enhancement EnhTypeRatio = Enhancment Type Ratio (equals 2:1). 50

51 Meadow Branch site mitigation calculations Mitigation Location Acres (appx) Functional Uplift (acreage equivalents) Enhance BLH from Low to Medium 26 acres 6.5 acres Enhance RSF from Low to High 8 6 Preserve BLH 10 0 Restore BLH remove logging road

52 Overall summary of mitigation credits Meadow Branch site Present calculations Present policy acre site acres of restoration. 26 acres of enhancement. 10 acres preservation. Since site only has 0.82 acres of restoration, therefore has very little overall mitigation value by itself. 52

53 Overall summary of mitigation credit Meadow Branch site with NC WAM With use of NC WAM 34 acres of enhancement which are equivalent to 12.5 acres of restoration and count toward no net loss calculations acres of restoration. 10 acres of preservation. Therefore, site has acres of restoration equivalents and is a very valuable mitigation site. 53

54 NC WAM / NC SAM documents available on Corps and DWR websites Corps RIBITS, Wilmington District, Assessment Tools NC WAM NC SAM Website NC WAM only u/ncwam-manual 54

55 Other information Recent publication (2014) in National Wetlands Newsletter 36 (4): Overview of NC WAM and NC SAM process. Recent publication (2015) in Environmental Practice 17: NC WAM including verification for headwater forest Peer-reviewed journal. Handouts available after session. 55

56 Questions? 56