Wetland Regulatory Aspects of Plant Community Mapping

Transcription

1 Wetland Regulatory Aspects of Plant Community Mapping Major Topics: Delineation and Classification Wetland Implications (in-kind) Monitoring of Wetland Sites Delineating Plant Community Types t new concept 1987 Corps of Engineers Wetlands Delineation Manual, Part III, states: Determine the type and layers in each plant community. MnRAM 3.0 uses wetland plant communities as laid out in Eggers and Reed as the basis for characterizing wetland vegetation BWSR seeding recommendations use wetland plant communities (consistent with Eggers & Reed) for BWSR approved seed mixes. Native Vegetation in Restored and Created Wetlands (Dan Shaw, BWSR September 2000) uses wetland plant communities as the basis for revegetation recommendations Wetland Type/Vegetation/Watershed Info Required in Past PART II: REPLACEMENT PLAN SUPPLEMENT For assistance in completing Part II, contact your Local Government Unit or a professional consultant 11. DESCRIPTION OF WETLAND IMPACTS: Complete the chart below: 1) Use one row of boxes for each wetland impact; 2) If your project has more than one wetland impact, reference your overhead view (part of Section 5) to this chart by identifying and labeling first impact and second impact on your overhead view; 3) If you are identifying only one wetland type within a given wetland impact area, use the first dotted line and leave the others blank; 4) If you have chosen to identify more than one wetland type within a given wetland impact area, use the extra dotted lines to indicate each wetland type, and identify predominant vegetation Type and size of impacted area for each separate wetland type within that impact area; 5) If you do not have access to some of this information, call your LGU or SWCD office for assistance. (Photocopy chart for more impacts, if needed.) DESCRIPTION OF WETLAND IMPACTS Wetland impact (as noted on overhead view) First impact Second impact Watershed County, Wetland type 1 Predominant name or Section, vegetation in number (if Township, impacted known) Range wetland area Watershed Multiple Impacts Size of area Existing land use in project impacted area (check all that apply) (in acres or square feet) Vegetation Housing Commercial Industrial Parks/recreation areas Highways and associated rights-of-way Forested Farmsteads/agricultural Vacant lands Public and semi-public (schools/gov t facilities) Airports Extractive (gravel pits/quarries) Other: 1 If you are identifying only one wetland type within a given wetland impact area, use the first dotted line and leave the others blank. If you have chosen to identify m than one wetland type within a given wetland impact area, use the extra dotted lines to indicate each separate wetland type, and identify predominant vegetation and s of impacted area for each separate wetland type with that impact area. New Application form requires Eggers & Reed Plant Communities TOTALS OF AREA(S) IMPACTED FOR EACH WETLAND TYPE ON CHART (indicate acres or square feet ) Type: 1: 1L: 2: 3: 4: 5: 6: 7: 8: R: 12. SPECIAL CONSIDERATIONS: Are you aware of any special considerations that apply to either the impact site(s) or the replacement site(s)? (Examples: the presence of endangered species, special fish and wildlife resources, sensitive surface waters, or waste disposal site.) If YES, list and describe briefly. 1

2 Delineating Plant Community Types for Regulatory Purposes Considerations: Overall Size of Wetland Minimum mapping unit - 10% of wetland size (rule of thumb) Area of Interest Wetland area on the project site For large wetland complexes, area of wetland in the immediate vicinity of the project Area of wetland impact is most important Considerations (continued) Precision of Mapping Resources Ability to distinguish differences on air photo Availability and accuracy of NWI, MLCCS, local mapping efforts, others Disturbance & Historical Condition Altered plant communities Altered hydrology Delineating Plant Community Types Primarily a mapping procedure, not a field delineation Step 1: Determine Size of Wetland for mapping purposes For large wetlands, common in NE Minnesota, evaluate part of wetland or area of interest Property boundary Wetland Area of interest Wetland area of interest Large wetland area Property Boundary Wetland boundary 2

3 Step 2 Estimate 10% of Wetland (minimum mapping unit) Reasonable wetland area of interest Different property boundary ~10% Minimum mapping unit = 10% Step 3 Identify potential plant communities from air photo About 10% Don t Count Open Water 3

4 Step 4 Field verify and refine plant community map Another example Mapping unit defined as wetland on the project site Marsh Marsh Preliminary mapping based on aerial photo interpretation Wet Meadow Delineating Plant Community Types Refined Plant Community Boundaries based on field review Use Common Sense! Remember the Purpose Alder thicket Deep Marsh Identification of specific wetland impact areas for use in matching replacement wetlands to impacted wetlands to achieve a similar combination of wetland functions and values (in-kind replacement) Apply the 10% rule of thumb when it makes sense, but also consider other factors that may justify a modified approach Wooded Wetland size Ability to distinguish on air photos Size of impact 4

5 What About Disturbed Wetlands? Cropped Wetlands Hayed Wetlands Sod Fields Forested Wetlands that were logged Partially Drained Wetlands Excavated Wetlands Question: Someone proposes impacting this wetland. What plant community would need to be replaced (for purposes of in-kind replacement)? Utilize Atypical Procedures to Estimate Natural Plant Community Type prior to disturbance Step 2 - Identify the probable affects on vegetation Step 1 Determine what the alteration was (farming, grazing, drainage, logging, etc.) Utilize air photos, field data (soils, hydrology indicators), observations, landowner statements, etc. Cleared or partially cleared Certain layers removed Selected species removed Burned, mowed, or heavily grazed Covered by fill Mortality due to excess water 5

6 Step 3 Characterize the Original Plant Community Type Examples How far back? Pre-settlement? 50 years ago? 25? Factors to Consider: Type, nature, and timing of disturbance Natural succession Current drainage area conditions (urban, farmed, natural) i.e. what is the normal condition of the site as it exists today? Pre-settlement was deep Partially drained and converted to wet meadow for 80 years It would be reasonable to consider this as a wet meadow. Recently harvested wooded swamp w looks like wet meadow It would be reasonable to consider this as a wooded swamp. Tools for Characterizing Original Vegetation Aerial photography Onsite Inspection Remnant hydrology indicators (water marks, subsidence) Soil characteristics (organic matter content, mottles) Remnant vegetation ID (stumps, plowed under plant leaves, etc.) Previous Inspections Adjacent Vegetation Nearby Reference Site NRCS Records (FSA slides) Personal Interviews NWI Maps Soil Survey Map 6

7 Use of Reference Wetland Example REGULATORY IMPLICATIONS OF PLANT COMMUNITY MAPPING Farmed Wetland Partially drained by tile Adjacent unfarmed wetland Similar topographic position Similar drainage area Farmed Wetland Reference Wetland Wetland delineation reports 1987 Manual: Include plant community types Sequencing considerations Plant community rankings in MnRAM can be used to compare relative quality for sequencing considerations 7

8 Page 73 of WCA Rule Book Subp. 4c. We ll go through some examples to de-mystify Wetland Ratio Calculation In-kind requirement Sum impacts for each type Compare wetland replacement credit type Calculate/adjust replacement ratio as necessary Example ac. hardwood swamp fill 1) In Wadena Co ac. shallow fill 0.2 ac. sedge meadow fill Who approved the sequencing on this one??? 2) In different Bank Service Area 3) repl. Hardwood = diff. type 4) By banking, so inadvance, ratio = 1.5:1 8

9 Calculate Required for Example (assumes >80% County) Same Example, modified to in-kind replacement Impact Type Wooded Impact area 0.5 ac In-Place Wetland Type (not In-kind) In-advance Applicable Ratio 1.5:1 Required 0.75 ac Impact Type Wooded Impact area 0.5 ac In-Place Wetland Type Wooded (in-kind) In-advance Applicable Required Ratio ac 0.25 ac (In-kind) 0.31 ac 0.25 ac (in-kind) 0.31ac Sedge meadow 0.2 ac (not In-kind) 1.5:1 0.3 ac Sedge meadow 0.2 ac Sedge meadow (in-kind) 0.25 ac TOTAL 0.95 ac 1.36 ac TOTAL 0.95 ac 1.19 ac Example #2 Landowner Requests driveway In St. Louis County Wetland Boundary Property Boundary Driveway Applicant & Consultant Submit Complete Application (on the third try) LGU Determines Sequencing has been adequately addressed 1) In St. Louis Co. Application documents the following impacts for the driveway: 1) Hardwood 0.82 acres 2) In different Bank Service Area 3) Hardwood repl. Hardwood = same type 4) By banking, so inadvance, ratio = 2) Marsh 0.14 acres 3) Alder Thicket 0.24 acres TOTAL IMPACT (after sequencing) 1.20 acres 9

10 Example #2, Driveway via Banking Example #3 Impact Type Hardwood Impact area 0.82 ac In-Place Wetland Type Hardwood (in-kind) In-advance Applicable Required Ratio 1.03 ac Farmer Smith proposes to drain wetlands on his property 0.14 ac Hardwood (not in-kind) 1.5: ac Alder Thicket 0.24 ac Hardwood (not in-kind) 0.30 ac TOTAL 1.20 ac LGU & TEP Determine Hardwood will adequately replace lost functions of alder thicket 1.54 ac Example #3 Example #3 Review Aerial photo history. Determine approximate size and location of wetlands. Determine Vegetation Communities via site visit 10

11 Example #3 Determine amount of each type of plant community 1) In Aitkin Co. 2) In Same Bank Service Area 3) Deep repl. wet meadow = different type 4) By banking, so inadvance, ratio = Example #3, Ag Land via Banking Project Specific replacement : Measures to Improve from a Plant Community, In-kind perspective Impact Type Impact area In-Place Wetland Type In-advance Applicable Ratio Required Consider plant community succession and set realistic timelines for establishment Wet Meadow 6.5 ac Deep Marsh (t in-kind) 8.1 ac For older community types (forested, shrub carr) ) establish successional goals for each monitoring year(s) Fresh (Wet) meadow TOTAL 2.2 ac 4.1 ac 12.8 ac (In-kind) Sedge meadow (t in-kind) 1:1 2.2 ac 5.1 ac 15.4 ac Establish clear plant community goals in replacement plan Increased scrutiny and consideration of matching hydrology to plant community type Increased scrutiny of early monitoring including construction monitoring Consider Financial Assurance to guarantee successful replacement 11

12 Project Specific : : Monitoring First year monitoring report Make reasoned plant community assumptions based on as-built and hydrology indicators The best time to implement corrective actions The WCA allows the LGU to order corrective actions at any time during d the monitoring period if they believe that the replacement goals will not be met. End of Monitoring Period What happens if in-kind requirements are not met? Corrective actions? Additional replacement required? Project Specific : Factors to Consider: Does the wetland meet replacement standards, just wrong types? Does the replacement wetland replace similar wetland functions as impacted wetland? How easily could it be corrected? Vegetation mgmt. Additional earthwork Outlet control structure changes Did the applicant make a good faith effort to achieve in-kind replacement? Project Specific : Good Faith Effort Was the vegetation plan followed? Evidence? Seed tags and receipts provided to the LGU Photo documentation of seeding Dates of seeding and maintenance activities provided along with supporting photo evidence Copies of bills and communications with seeding and veg. management contractor. Monitoring Reports (ideally the above information would be included in the monitoring reports). Project Specific : Monitoring Important Documentation: Plan Approval Date Plan Modification Dates Date of Wetland Restrictions & Covenants Form Recording Construction Start and end Dates Native Seeding Dates LGU Inspection Dates Date of any corrective actions ordered/completed Date As-Built Plan Received Date Monitoring Reports Received Date As-Built Wetland Delineation Received Final Wetland Numbers: Wetland Creation Size (NWC, PVC) Wetland Restoration Size (NWC, PVC) Upland Buffer Size (NWC,PVC) Other credit options Date of Certification Decision by banking is much easier for the applicant and the LGU! 12