Goal

Information Considered

Proposed Standards

Notes

(Prevention) Enclosing, straightening, and relocating streams should be discouraged during all new development

·        Ohio EPA troubled by culverting, potential conflict with Clean Water Act § 401 program requirements

·        Columbus Metropolitan Facilities Plan Update, Response to Comment p. 21-22 (November 2, 2000)

·        Darby Creek Watershed Stormwater Management Strategies and Standards, Principle 22 (December 2000)

·        Clean Rivers Spring from Their Source:  The Importance & Management of Headwater streams (Ohio EPA Fact Sheet, November 2000)

All watercourses shall remain open and shall not be enclosed within a storm sewer or other engineered structure.

The proposed standard is consistent with all information sources considered.

(Prevention) Maintain 100 year flood plain as close to its natural state as possible so that it can perform its inherent function of flood storage

·        Columbus Metropolitan Facilities Plan Update, Response to Comment p. 21-22 (November 2, 2000)

·        Darby Creek Watershed Stormwater Management Strategies and Standards, Principle 16 (December 2000)

·        Conservation Development Resource Manual, Section 4A (1998 The Western Reserve Resource Conservation Development Council)

·        Hellbranch Run Plan (MORPC, Draft 9/25/2000)

Neither the total stormwater storage capacity nor the total area of the 100-year floodplain shall be reduced. 

The proposed standard is consistent with all four information sources considered.

(Prevention) Create/protect vegetated riparian buffer system along watercourses

·        Ohio Department of Natural Resources Scenic River Forest Buffers (11/18/93)

·        Ohio’s Streamside Forests: The Vital, Beneficial Resource (ODNR 1998)

·        Westland Area Plan (1994)

·        Franklin County Zoning Resolution § 650, Big and Little Darby Creeks Critical Resource Protection District (May 4, 1994)

·        MORPC Model Watercourse Protection Ordinance (March 30, 1999)

·        Riparian Buffers:  Technical Information for Decision Makers (Chagrin River Watershed Partners, Inc. Technical Paper Series #1, November 1997, Revised February 1999)

·        Franklin County Subdivision Regulations § 406 Watercourse Protection Area (June 2000)

·        Darby Creek Watershed Stormwater Management Strategies and Standards, Principle 16 (December 2000)

·        Conservation Development Resource Manual, Section 5B (1998 The Western Reserve Resource Conservation Development Council)

·        Chagrin River Watershed Partners, Inc. Model Ordinance (December 2000)

·        Columbus Metropolitan Facilities Plan Update, Response to Comment p. 21-22 (November 2, 2000)

·        Hellbranch Run Plan (MORPC, Draft 9/25/2000)

·        Model Ordinances To Protect Local Resources – Aquatic Buffers (U.S. EPA)

·        Schueler, Tom, “The Architecture of Stream Buffers” from Watershed Protection Techniques Vol. 1, No. 4 – Summer 1995 (Center for Watershed Protection)

·        Chesapeake Bay Riparian Handbook:  A Guide for Establishing and Maintaining Riparian Forest Buffers (May  1997, Revised June 1998)

·        Clean Rivers Spring from Their Source:  The Importance & Management of Headwater streams (Ohio EPA Fact Sheet, November 2000)

Establishes a stream bank buffer containing either: (1) the entire 100 year floodplain; or (2) the riparian buffer, whichever is greater.  The riparian buffer is determined as follows:

(a)    For Hellbranch Run, the Clover Groff Ditch, and the Hamilton Ditch, the riparian buffer is 120 feet upland from the ordinary high water mark; or

(b)    For any tributary, named or unnamed, to the Hellbranch Run, the Clover Groff Ditch, or the Hamilton Ditch exhibiting a discernable high water mark, the riparian buffer is 75 feet upland from the ordinary high water mark.

·        All of the considered information sources advocate buffer protection.

·        The Darby Creek Watershed Stormwater Management Strategies and Standards, Conservation Development Resource Manual and model ordinance, Chagrin River Watershed Partners, Inc. Technical Paper Series #1 and Model Ordinances To Protect Local Resources – Aquatic Buffers (U.S. EPA) all advocate including the entire 100-year flood plain within the buffer.  The Chagrin River Watershed Partners, Inc. Technical Paper also advocates buffering the flood plain itself when possible.  MORPC Model Watercourse Protection Ordinance advises that the buffer can be extended to include the floodplain after balancing considerations such as “developability,” development patterns, property values, and resource extraction potential.

·        The Franklin County Subdivision Regulations § 406 Watercourse Protection Area (June 2000) establish a 120’ buffer for the Hellbranch Run, Hamilton Ditch, and Clover Groff Ditch.

·        The MORPC Model Watercourse Protection Ordinance and Chagrin River Watershed Partners, Inc. Technical Paper Series #1 suggest buffer widths of 120’/75’/25’ based upon the drainage area of the watercourse.  The U.S. EPA advises a minimum 100’ base buffer with additional buffer based upon stream order, percent slope, floodplain, and wetlands.   

(Minimization) Advocate open space development that incorporates smaller lot sizes

·        West Columbus Interim Development Concept (1991)

·        Darby Creek Watershed Stormwater Management Strategies and Standards, Principle 10 (December 2000)

·        Southeast Area Plan (Adopted by City Council January 31, 2000)

·        Conservation Development Resource Manual, Section 3A (1998 The Western Reserve Resource Conservation Development Council)

·        Gibbons, Jim, “Addressing Imerviousness In Plans, Site Design and Land Use Regulations” (Nonpoint Education for Municipal Officials, Technical Paper, No. 1)

·        Arnold, Chester and C. James Gibbons, “Impervious Surface Coverage:  The Emergence of a Key Environmental Indicator” (Journal of American Planning Association, Vol. 62, No. 2, Spring 1996)

·        NEMO Project Fact Sheet 3, “Impacts of Development on Waterways”

·        NEMO Project Fact Sheet 4, “Strategies for Coping with Polluted Runoff”

·        Hellbranch Run Plan (MORPC, Draft 9/25/2000)

Forty percent (40%) open space reservation.

·        Conservation Development Resource Manual recommends that the open space requirement be a minimum of 40 percent of the total project area.  It also recommends standards based on desired density of development: for areas desired to be “suburban” (more than 2 units per acre) the open space reservation is 40%; for “semi-rural” (between 2 units per acre and 2 acre lots) the reservation is 50%; and for “rural” (density of 2 acre lots or less) the reservation is 60%.

·        The Southeast Area Plan advocates 35% open space.

(Mitigation) Stormwater Best Management Practices required

·        Darby Creek Watershed Stormwater Management Strategies and Standards, Principle 21 (December 2000)

·        Columbus Metropolitan Facilities Plan Update, Response to Comment p. 21-22 (November 2, 2000)

·        Hellbranch Run Plan (MORPC, Draft 9/25/2000)

Detention and Treatment.  Stormwater generated as the result of development shall be detained and treated by extended detention, natural or constructed wetlands, or other approved means, outside of the 100-year floodplain boundaries, to the extent necessary to meet water quality pollutant removal goals, reduce channel erosion, prevent overbank flooding, and pass extreme floods

Conveyance.  All stormwater generated as the result of development shall flow into the nearest receiving stream or approved storm sewer drainage system without increasing flood depths or causing standing water either upstream or downstream.  To assure that this goal will be achieved, the applicant must affirmatively demonstrate that between the proposed development site and the point in the receiving watercourse at which the proposed development site is 10% of the total area tributary, post-development stormwater volumes will be less than or equal to pre-development stormwater volumes for 5, 10, and 100-year frequency storms. 

These standards are consistent with Darby Creek Watershed Stormwater Management Strategies and Standards, Principle 21 (December 2000).