7th WetPro Forum

7th WetPro Forum:Lake County’s Watershed Development Ordinance Proposed Wetland AmendmentsFebruary 18, 2005: 

7th WetPro Forum: Lake County’s Watershed Development Ordinance Proposed Wetland Amendments February 18, 2005 Presenters: Joy Corona – Bleck Engineering Glenn Westman – Lake County SMC Joseph Hmieleski – Lake County SMC

WDO Amendment Process: 

WDO Amendment Process Why amend WDO? How Does Process Work? Staff  Technical Advisory Committee  SMC  County Board Anticipated Adoption Schedule? TAC complete ~ Feb/March 2005 60-day Public Comment Period start date ~ March/April 2005 SMC Approval ~ late July/early August 2005 County Board Approval ~~August 2005

Definitions and Clarifications: 

Definitions and Clarifications Amendment 11 March 1992 data form (or similar) Photographs only required for representative data points Number of photographs dependant on community types

Definitions and Clarifications: 

Definitions and Clarifications Amendment 37 Used for HQAR assessments, NOT for USACE vegetation Clarifies that dominance refers to individual vegetative stratum Different procedures for determining dominance in each vegetative layer

Dominant Definition - Current: 

Dominant Definition - Current Dominant: a dominant plant species is one that comprises greater than 50% of the total vegetated wetland acreage

Definitions and Clarifications: 

Definitions and Clarifications Amendment 37 New Version: Trees Herbs Shrubs Saps. Vines S. canadensis – 20% **C. lacustris – 60% A. lateriflorus – 10% A. negundo – 40% U. americana – 10% Q. macrocarpa – 10% Subunit - 0.5 m2 quadrat - percent cover - DBH - percent of total DBH

Definitions and Clarifications: 

Definitions and Clarifications Amendment 37A New definition Specifies diameter, height and areal coverage First part follows Cowardin

Definitions and Clarifications: 

Definitions and Clarifications Amendment 39 – Revised Isolated Waters of Lake County Definition Revised to clarify areas that are, or are not, excluded Exclusions Do Not Apply to: HQARs (new) Mitigation areas Publicly funded wetland restoration areas (new)

Definitions and Clarifications: 

Definitions and Clarifications Amendment 39 – Revised Isolated Waters of Lake County Definition Excluded from IWLC: Excavations and impoundments permitted by jurisdictional authority (e.g., SMC, municipality) Excavations and impoundments, “permitted by right” (mostly earlier than 1992) Excavated in upland soils based on 1970 SCS Soil Survey (Exceeds 40% of excavated area) For “W” soil designations - connect adjoining soils boundaries

IWLC – Exclusion for Excavation Example: 

IWLC – Exclusion for Excavation Example

IWLC – Exclusion for Excavation Example: 

IWLC – Exclusion for Excavation Example Overlay soil types

IWLC – Exclusion for Excavation Example: 

IWLC – Exclusion for Excavation Example Connect hydric soils through “W” areas

IWLC – Exclusion for Excavation Example: 

IWLC – Exclusion for Excavation Example Excavated in upland soils 15% excavated in upland soil  Regulated

Definitions and Clarifications: 

Definitions and Clarifications Amendment 39 – Revised Isolated Waters of Lake County Definition Excluded from IWLC: Areas created by incidental construction grading Roadside Ditches

Definitions and Clarifications: 

Definitions and Clarifications Amendment 46 Bathymetrical survey required to verify “open water” Low potential for rooted vegetated growth Consistent with TRM wet detention design Used in other parts of WDO (detention and mitigation) Any area less than 3 foot depth considered “wetland”

Wetland Hydrology: 

Wetland Hydrology Amendments #53, 90 and 92

Overview: 

Overview 80-150 standard still applies (except for IWLC used for detention meeting 85% vegetation criteria or open waters) Clarifications and design criteria added

Release Rate: 

Release Rate Detention facilities (site) must still comply with release rate criteria (for both 2-yr and 100-yr events) Release rate to IWLC subtracted from allowable, secondary outlet sized for remaining allowable flow A minimum 4” is allowed from both IWLC and secondary outlets

Slide19: 

Draft TRM Figure 5-c

Draft TRM Figure 5-c con’t: 

Draft TRM Figure 5-c con’t

Minimum Submittal Requirements: 

Minimum Submittal Requirements Exhibit delineating pre-construction and with-project (p&w) drainage areas P&W CN computations P&W Runoff Volume for the 2-yr, 24-hr event Must maintain any existing wetland outlet controls hydrologic function

Determination of allowable V: 

Determination of allowable V Meet 80-150 for on-site portion of watershed (not total wetland watershed) If partial wetland fill – reduce existing volume (prior to calculating 80-150) by proposed/existing ratio

80-150Based on On-Site Tributary Area: 

80-150 Based on On-Site Tributary Area On-Site Tributary Area 8-ac Wetland Area 5-ac Total Tributary Area 30-ac On-Site Wetland Area 2-ac Existing Runoff V 8ac (CN 74) = 0.53 AcFt Proposed Runoff V 8ac (CN 80) = 0.74 AcFt (0.74/0.53)*100 = 140% 80 < 140 <150 OK

80 – 150Partial Fill: 

80 – 150 Partial Fill Wetland Area 5-ac Total Tributary Area 30-ac On-Site Wetland Area 2-ac Ex. On-Site Trib. Area 8-ac Existing/Proposed Wetland 2ac / 5ac = 0.4 Existing V = 0.53 AcFt Reduce Existing V = 0.53 * 0.4 = 0.21 AcFt Proposed V 3ac (CN 80) = 0.28 AcFt (0.28/0.21)*100 = 133% 80 < 131 < 150 OK Pr. On-Site Trib Area 3-ac

CN Determinations: 

CN Determinations Pre-construction based on LC Soil Survey soil types and runoff potential With-project Areas that will be graded for structural backfill change to soil types’ highest runoff potential Areas not disturbed retain pre-construction runoff potential Areas deed/plat restricted for native plantings may develop lower runoff characteristics

Existing Soil Type BMass graded Subdivision: 

Existing Soil Type B Mass graded Subdivision Use CN 74 for Ex. Runoff Volume Calc Use CN 85 for Pr. Runoff Volume Calc

Calculating Wetland Impact: 

Calculating Wetland Impact Hydrologic impact is in addition to other IWLC impacts IWLC wholly onsite: total area not meeting hydrology considered impact IWLC partially onsite: Onsite trib. DA * remaining wetland area Total trib. DA

Wetland Impact: 

Wetland Impact Total Tributary Area 30-ac On-Site Wetland Area 2-ac Pr. On-Site Trib Area 3-ac CN 80 V = 0.36 AcFt Ex. On-Site Trib. Area 8-ac Direct Wetland Impact = 2ac Ex. V = 0.21 AcFt Pr V = 0.36 AcFt (0.36/0.21)*100 = 171% Hydrologic Impact (8ac/30ac) * (5-2) = 0.8ac Total Impact 2ac + .8ac = 2.8-ac Ex. Wetland Area 5-ac

Wetland Mitigation: 

Wetland Mitigation Amendments 13-16, 45, 71, and 80

Mitigation : 

TAC Approved: Mitigation required in Lake County for ANY impacts to HQARs (currently >1/4 ac.) Mitigation required in Lake County for > 1/10 impacts to non-HQARs (currently >1/4 ac.) SMC Staff Recommendation: Mitigation required in Lake County for ANY impacts to HQARs (currently >1/4 ac.) Maintain >1/4 ac. threshold for non-HQARs Mitigation Amendment 13 – Proposed Mitigation Thresholds

Mitigation : 

Removal of “on-site” creation requirement provides flexibility to meet 1:1 replacement (no net loss) at approved offsite location or mitigation bank Enhancement credit for non-farmed wetlands remains 25% (0.25 acre credit for each acre enhanced) Mitigation Amendment 15 – Enhancement & Mitigation Flexibility

Mitigation : 

Second sentence added to clarify total mitigation cost also includes 5-year monitoring & management SMC requests letter of credit (LOC) for 110% of total mitigation cost. Contact SMC for example LOC. Mitigation Amendment 16 – Mitigation Surety

Mitigation : 

“Open waters” >3’ deep per new definition (see Amendment no. 46) Bathymetric survey required to verify open water zone. Impacts to open water areas mapped as ADID (HQAR) on Lake County Wetland Inventory maps still require minimum 3:1 mitigation. Mitigation Amendment 45 – Mitigation Ratio for “Open Water”

Mitigation : 

Clarifies that wetlands to be created, restored or enhanced for mitigation credit shall meet the “standard” buffer requirements in Section IV.B.1.i. of the WDO (e.g., 50’ avg. – 25’ min. for mitigation wetlands >2.5 ac.) Enhanced uplands or wetland edges used to meet buffer requirements may receive 25% credit per acre toward total mitigation requirement (after 1:1 creation achieved). Must meet Appx. N performance standards. Created/restored wetland edges used to meet buffer requirements may receive 75% credit per acre toward total mitigation requirement (after 1:1 creation achieved). Must meet Appx. N performance standards. Mitigation Amendment 71 – Mitigation Area Buffers

Mitigation : 

“Condensed” version of Corps-Chicago District’s Mitigation Requirements, 2004. Applies only to mitigation plans for IWLC impacts (i.e., wetland creation or enhancement onsite or at approved offsite location – excluding mitigation banks). Corps may require additional information for mitigation for impacts to “Waters of the U.S.” Provides standard format and guidelines for preparing the Project Mitigation Document (PMD). Consistency in PMD preparation will expedite SMC’s review process. Mitigation Amendment 80 – Appendix N: SMC’s Mitigation Guidelines for IWLC

Mitigation : 

Wetland performance standards generally same as Corps (e.g., FQI >20, mean C >3.5, mean W coefficient <0 after 5 years) May receive 25% credit per acre for buffers (after min. 1:1 wetland creation), BUT must meet vegetation performance standards. Following standards are for prairie buffers (performance standards for other community types - forest, savanna, etc., to be established on site-specific basis): Mean C >2.5 and FQI >15 by end of 5th year No area >100 ft2 shall be devoid of vegetation by end of 5th year None of the three dominant species shall be invasives, such as Cirsium arvense, Melilotus spp., Poa pratensis, Ambrosia artemisiifolia, etc. Mitigation Amendment 80 – Appendix N: SMC’s Mitigation Guidelines for IWLC (Cont’d)

Detention “in” IWLC: 

Detention “in” IWLC Amendments #17, 62 and 63

Detention OK in following IWLC: 

Detention OK in following IWLC Farmed Wetlands Non-farmed, non open water, 85% coverage Reed canary grass Purple loosestrife Common reed Buckthorn Open water not HQAR

When does 80-150 apply?: 

When does 80-150 apply? When basin is also being used as wetland mitigation enhancement credit Farmed wetlands Does NOT apply to IWLC meeting 85% vegetation criteria or open waters

Design Standards: 

Design Standards Re-establish vegetation using Native Plant Guide Must meet WQ upstream of facility – cannot take partial credit for buffers or plantings etc.

Addressing WQ: 

Addressing WQ Volume based sediment or infiltration basin Permanent Pool sized for 2-yr, 24-hr event and minimum 4-ft deep Structural measures

Slide42: 

Draft TRM Figure 5-b

Draft TRM Figure 5-b con’t: 

Draft TRM Figure 5-b con’t

What is still considered impact to existing wetland area?: 

What is still considered impact to existing wetland area? Enhancement – Category IV Fill or loss – Category I, II, III

Enhancement vs. Fill/Loss: 

Enhancement vs. Fill/Loss Enhancement No impact Fill Cut Wetland Limits Wetland Limits Fill Fill Fill/Loss Impact

Mitigation Credit: 

Mitigation Credit Creation of wetlands for mitigation shall not take place within detention facilities Enhancement of farmed wetlands (per E.5.a) may be used for 80% of mitigation requirement

Mitigation Plan : 

Mitigation Plan If enhancement credit requested, std. mitigation requirements of E.4 still apply If no credit requested mitigation requirements of E.4 do not apply

Jurisdictional Determination Guidance - USACE: 

Jurisdictional Determination Guidance - USACE Mike Murphy