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HomeMy WebLinkAboutCOUNCIL - AGENDA ITEM - 05/06/2014 - RESOLUTION 2014-033 SUPERSEDING RESOLUTION 2013-04Agenda Item 19 Item # 19 Page 1 AGENDA ITEM SUMMARY May 6, 2014 City Council ITEM POSTPONED TO MAY 20, 2014 STAFF Ken Sampley, Stormwater/Floodplain Program Mgr SUBJECT Resolution 2014-033 Superseding Resolution 2013-049 and Authorizing the Execution of a Revised First Amendment to the Intergovernmental Agreement Establishing the Boxelder Basin Regional Stormwater Authority. EXECUTIVE SUMMARY The purpose of this item is to approve a revised First Amendment to the Boxelder Basin Regional Stormwater Authority (BBRSA) in place of the First Amendment that was authorized by the adoption of Resolution 2014- 049. The Revised First Amendment: • Authorizes the BBRSA to determine and make minor revisions to properties within the Service Area of the BBRSA by designating areas as “non-tributary areas”, and to grant fee credits to other areas within the Service Area; • Authorizes the BBRSA to accept loans from the Colorado Water Conservation Board (CWCB) to fund the design and construction of the remaining regional stormwater projects; and, • Establishes a sunset provision that terminates collection of stormwater fees and charges either twenty years after the effective date of this Amendment, provided there is agreement regarding the operation and maintenance responsibilities for the projects, or upon completion of all regional stormwater projects, payment of all debt incurred by the BBRSA, agreement as to payment of any BBRSA obligations to Members and disbursement of any remaining revenues and agreement among the Members as to any continuing obligation for operation and maintenance of the projects. STAFF RECOMMENDATION Staff recommends adoption of the Resolution. BACKGROUND / DISCUSSION The Boxelder Creek Watershed encompasses over 265 square miles and extends from just north of the Wyoming border to the Poudre River on the south. Several local governments have worked together since 2005 to identify ways to mitigate flood hazards within the area that is tributary to Boxelder Creek from County Road 70 north of Wellington south to where Boxelder Creek floodwaters join the Cache La Poudre River. The Boxelder Creek 100-Year floodplain impacts approximately 4,900 acres of land within the regional area. Due to the numerous split flows and diversions that occur, the potential for overtopping frequently used roads and the probability of the existing conveyance system to become blocked, there is the potential for loss of life and/or bodily injury during the 100-Year Flood. In August 2008, the City of Fort Collins, Larimer County and Town of Wellington entered into an intergovernmental agreement to establish the Boxelder Basin Regional Stormwater Authority (BBRSA) and fund the design and construction of regional stormwater improvements. In 2012, the Town of Timnath entered into an intergovernmental agreement with the BBRSA to financially participate in the design and Agenda Item 19 Item # 19 Page 2 construction of regional stormwater improvements. The originally proposed First Amendment to the BBRSA Intergovernmental agreement was approved by both the City of Fort Collins and the Town of Wellington in May 2013. Larimer County, however, expressed concerns regarding the need to identify and fund specific improvements to County Road 52 and to better define the sunset language provision included in the amendment. A staff update on the BBRSA and associated projects on Boxelder Creek was presented at the January 28, 2014 City Council Work Session. In 2014, all parties executed the County Road 52 Improvements IGA to address Larimer County’s concerns. Accordingly, the BBRSA Master Plan has been updated and revised to consist of the following regional stormwater projects:  Diversion of Coal Creek to Clark Reservoir (Clark);  East Side Detention Facility (ESDF);  County Road 52 Improvements (CR 52 Improvements); and  Larimer and Weld Canal Crossing Structure (LWCCS). Larimer County has proposed a revision to the First Amendment to the BBRSA Intergovernmental Agreement that specifies a twenty-year sunset provision on the collection of stormwater fees and charges pending agreement of the parties regarding the on-going operations and maintenance of the regional stormwater projects. FINANCIAL / ECONOMIC IMPACTS In light of the BBRSA Stormwater Master Plan revisions, an update of the estimated Benefit/Cost Ratio of the regional stormwater projects was completed to confirm the financial benefits. The table below uses information on damage losses from the 2006 Boxelder Creek Regional Stormwater Master Plan and compares the losses with the current estimated construction costs for the remaining BBRSA projects (ESDF, LWCCS, and CR52 Improvements). 1Present Worth Damage Losses Estimated in 2006 Master Plan 10/30/2013 Boxelder Creek Reach Potential Damages at Existing Conditions Potential Damages After Construction Resulting Benefits (Damage Reductions) Middle Boxelder Creek (CR54 to I25) $ 9,990,993 $ 5,000,000 $ 4,990,993 Boxelder Overflow $ 9,007,028 $ - $ 9,007,028 Lower Boxelder Creek (I25 to Poudre) $ 2,015,535 $ 811,806 $ 1,203,729 Boxelder I 25 Split $ 10,224,807 $ - $ 10,224,807 Cooper Slough $ 27,344,409 $ 8,623,624 $ 18,720,785 Cache La Poudre Overflow $ 2,311,180 $ 220,493 $ 2,090,687 Total $ 60,893,952 $ 14,655,923 $ 46,238,029 2 Current Construction Cost Estimate (ESDF, LWCCS& CR 52 Improvements) $ 11,700,000 Estimated Benefit/Cost Ratio 3.95 1 Source: T able C-3 Appendices BOXELDER CREEK REGIONAL ST ORM WAT ER M AST ER PLAN October 2006 2 Initial Total Costs to be offset by Authority Revenue & TDA contributions & Additional Fu n ding from New IGA Review of the table shows an updated Benefit/Cost Ratio of 3.95. In most instances, a B/C ratio of 1.5 or 2 is considered very good. Such a high B/C ratio is very unusual and demonstrates the dramatic benefits that construction of the BBRSA projects has with regard to the reduction in damages from a 100-Year flood event. Summary – Fort Collins Benefits There are significant financial benefits and reductions in flood damage to properties located with the City of Fort Collins and its GMA as presented at both the January 28, 2014 Council Work Session and March 18, 2014 Regular Council Meeting. Highlights of the benefits include: Agenda Item 19 Item # 19 Page 3 Cooper Slough  The BBRSA regional stormwater projects will eliminate the westerly Boxelder Creek overflow that extends south along the east side of Interstate Highway 25.  A savings of $11.3 Million in reduced stormwater infrastructure costs.  Removal of 130 acres of land from the 100-Year floodplain.  Reduces flooding damage to existing properties at the Mulberry Road / Interstate Highway 25 interchange. Boxelder Creek  The BBRSA regional stormwater projects will eliminate the westerly Boxelder Creek overflow that extends south along the east side of Interstate Highway 25.  There is a $6 million savings in stormwater infrastructure required for roads within the Fort Collins GMA.  There is a $2.1 million savings in stormwater improvements at Boxelder Creek / Prospect Road.  Removal of 650 acres of land from the 100-year floodplain. 20 Year Stormwater Fee and Charge Sunset Provision The revised language in the First Amendment states that the BBRSA shall terminate collection of stormwater fees and charges twenty years after the effective date of the Amendment provided there is agreement among the Members with regard to any continued obligation of the Authority which extends beyond such termination for operation and maintenance responsibilities for the Coal Creek Flood Mitigation, ESDF, CR 52 Improvements, and LWCCS projects, or upon the occurrence of all of the following contingencies (a) through (e), whichever first occurs: (a) Completion of the East Side Detention Facility/Gray Lakes and Larimer/Weld County Canal Crossing Structure projects; (b) Payment in full of the loan from the CWCB and any other obligations of the Authority; (c) Agreement among the Members with regard to any continued obligation of the Authority which extends beyond the termination of collection of fees and charges by the Authority including, but not limited to, operation and maintenance responsibilities for the Coal Creek Flood Mitigation, the East Side Detention Facility/Gray Lakes, and Larimer/Weld County Canal Crossing Structure projects.; (d) Agreement among the Members as to payment of any Authority obligation to the Members for matching funds of the Members for the FEMA Pre-Disaster Mitigation Grant in the approximate amount of one million dollars ($1,000,000); and, (e) Agreement among the Members as to the disbursement of any revenues of the Authority which remains after the Authority has finalized all of the administrative and organizational requirements necessary to terminate collection of fees and charges by the Authority including, but not limited to, any required budgets, audits, and filings with any state or federal authority. The current financial scenarios indicate that the CWCB loans are anticipated to be paid off within 15 years. This is well within the twenty year time period included in the revised First Amendment language. It should also be noted that the twenty year time frame is also contingent on the requirement that Fort Collins, Larimer County and Wellington have reached agreement with regard to the long-term operations and maintenance of the regional stormwater projects. ENVIRONMENTAL IMPACTS The BBRSA has already received Endangered Act Species (ESA) clearance for its projects and is working with the U.S. Army Corps of Engineers (USACE) to receive the required 404 Permit. In accordance with the language in the original Boxelder IGA -- the location, size and impacts of any BBRSA or Fort Collins/Timnath stormwater improvements projects built on or in the vicinity of the Arapaho Bend Natural Area east of Interstate Highway 25 shall be minimized to the extent reasonably possible and that all construction activities and improvements shall be sensitive to the natural features of the affected property. Any area impacted by construction activities shall be restored to pre-construction natural conditions to the extent reasonably possible, using native vegetation. Agenda Item 19 Item # 19 Page 4 As a result of the relocation of the ESDF downstream, the Middle Boxelder Creek improvements were eliminated, reducing potential impacts on the section of Boxelder Creek from County Roads 48 to 54. PUBLIC OUTREACH Information on the BBRSA and progress on its regional projects is presented monthly at the BBRSA Board of Directors meeting which is held at 4:00 PM the fourth Wednesday of each month at the Leeper Center, 3800 Wilson Avenue, Wellington, Colorado. The Board Meeting agendas and minutes along with relevant studies, mapping and other information are available for review at the following BBRSA website hyperlink: http://www.boxelderauthority.org/. In addition, the BBRSA maintains a mailing list of parties who have expressed interest in receiving information and regularly distributes Board Meeting agendas and materials. The BBRSA also publishes and distributes a quarterly newsletter which provides information and updates on the authority and its programs. Comprehensive updates on the BBRSA were presented at the recent public meetings listed below:  January 28, 2014 City Council Work Session  February 26, 2014 BBRSA Board of Directors Work Session  March 18, 2014 City Council Regular Meeting. ATTACHMENTS 1. Boxelder Creek Watershed -- Project Map (PDF) 2. Powerpoint presentation (PDF) EAST SIDE DETENTION FACILITY (ESDF) and COUNTY ROAD 52 IMPROVEMENTS LARIMER / WELD CANAL CROSSING STRUCTURE (LWCCS) BOXELDER CREEK AT I-25 LAKE CANAL CROSSING OF BOXELDER CREEK BOXELDER CREEK OUTFALL AND PROPSECT ROAD IMPROVEMENTS BOXELDER CREEK WATERSHED -- PROJECT MAP 1 1 First Amendment to Boxelder Basin Regional Stormwater Authority City Council Meeting May 6, 2014 Kenneth C. Sampley, P.E. Stormwater and Floodplain Program Manager City of Fort Collins 2 Executive Summary The purpose of this item is to: Supersede Resolution 2014-049 and Authorize the Execution of a Revised First Amendment to the IGA Establishing the Boxelder Basin Regional Stormwater Authority. ATTACHMENT 2 2 3 BOXELDER CREEK WATERSHED _____ Project Map 4 • Original First Amendment approved by both Fort Collins and Wellington in May 2013. • Larimer County  Concerns regarding – County Road 52 Improvements – Sunset Language provision • In March/April 2014, all parties executed the County Road 52 Improvements IGA to address Larimer County’s concerns. • Larimer County proposed a revision to the First Amendment regarding sunset language – Approved by both Larimer County and Wellington. First Amendment -- Background 3 5 • “Non-tributary areas” and fee credits in Service Area; • Accept loans from the Colorado Water Conservation Board (CWCB) to fund the design and construction of the remaining regional stormwater projects; and, • Sunset provision that terminates stormwater fees: – 20 years after date of First Amendment (if O & M responsibilities agreed to); OR – Upon completion of all projects, payment of all debt and BBRSA obligations, and agreement on operations and maintenance. First Amendment -- Revised 6 Executive Summary The purpose of this item is to: Supersede Resolution 2014-049 and Authorize the Execution of a Revised First Amendment to the IGA Establishing the Boxelder Basin Regional Stormwater Authority. - 1 - RESOLUTION 2014-033 OF THE COUNCIL OF THE CITY OF FORT COLLINS SUPERSEDING RESOLUTION 2013-049 AND AUTHORIZING THE EXECUTION OF A REVISED FIRST AMENDMENT TO THE INTERGOVERNMENTAL AGREEMENT ESTABLISHING THE BOXELDER BASIN REGIONAL STORMWATER AUTHORITY WHEREAS, on July 15, 2008, the City Council approved Resolution 2008-068, authorizing an intergovernmental agreement with Larimer County and the Town of Wellington to form the Boxelder Basin Regional Stormwater Authority (the “Authority”), to fund and implement the regional stormwater improvements outlined in the Boxelder Regional Stormwater Master Plan (the “Master Plan”); and WHEREAS, on August 20, 2008, the intergovernmental agreement to form the Authority (the “Agreement”) was finalized and signed by all parties, and the Authority was subsequently organized; and WHEREAS, since its organization, the Authority has completed the design and construction of the Coal Creek Flood Mitigation Project and has preliminarily designed the two remaining regional stormwater projects contemplated in the Master Plan; and WHEREAS, in order to move forward with the remaining projects, the Authority has identified possible funding in the form of a loan from the Colorado Water Conservation Board (“CWCB”), to be repaid with Authority stormwater fees collected from within the Authority’s service area; and WHEREAS, the Agreement calls for the members of the Authority to approve any borrowing by the Authority; and WHEREAS, in addition to the approval of the proposed borrowing from CWCB, the Board of Directors of the Authority (the “Board”) has recommended that the members of the Authority amend the Agreement to designate certain non-tributary areas and provide for fee credits to areas within the Authority service area that do not contribute stormwater flows to the Basin; and WHEREAS, the Board has further recommended that the members of the Authority amend the Agreement to sunset the Authority upon completion of the remaining Master Plan projects, payment of all debt incurred, and agreement among the members as to continuing obligations for ownership, operation and maintenance of the improvements constructed by the Authority; and WHEREAS, on May 21, 2013, the City Council adopted Resolution 2013-049, authorizing an amendment to the Agreement that incorporated the terms described above; and WHEREAS, since the adoption of Resolution 2013-049, additional revisions to the Agreement have been proposed by Larimer County, and the amendment as approved by the City Council has not been executed; and - 2 - WHEREAS, Larimer County has proposed that the Agreement language regarding the sunset of the Authority be revised; and WHEREAS, a First Amendment to the Agreement reflecting the recommendations of the Board as set forth in the originally approved amendment, as well as the revisions requested by Larimer County, has been prepared by Authority staff (the “First Amendment”), and is attached hereto as Exhibit “A” and incorporated herein by this reference; and WHEREAS, the Town Board of Wellington and the Board of County Commissioners of Larimer County have approved the First Amendment in substantially the form attached hereto; and WHEREAS, the City Manager has recommended that the City Council approve the First Amendment. NOW, THEREFORE, BE IT RESOLVED BY THE COUNCIL OF THE CITY OF FORT COLLINS as follows: Section 1. That the City Council hereby finds that the approval of the First Amendment is in the best interests of the City in order to facilitate the completion of the Master Plan improvements and provide for the fulfillment by the Authority of its intended purposes and objectives for stormwater improvements in the Boxelder Basin. Section 2. That the City Council hereby approves the First Amendment and authorizes and directs the Mayor to execute the First Amendment on behalf of the City in substantially the form attached hereto as Exhibit “A,” together with such additional or modified terms and conditions as the City Manager, in consultation with the City Attorney, determines to be necessary and appropriate to protect the interests of the City and advance the purposes set forth in this Resolution. Section 3. That the terms of this Resolution supersede and replace Resolution 2013- 049, which shall be of no further force or effect. Passed and adopted at a regular meeting of the Council of the City of Fort Collins this 6th day of May, A.D. 2014. _________________________________ Mayor ATTEST: _____________________________ City Clerk FIRST AMENDMENT TO INTERGOVERNMENTAL AGREEMENT FOR STORMWATER COOPERATION AND MANAGEMENT THIS FIRST AMENDMENT entered into this day of , 20 , by and among the BOARD OF COMMISSIONERS OF LARIMER COUNTY, COLORADO, (the “County”), the CITY OF FORT COLLINS, COLORADO, a municipal corporation (the “City”), and the TOWN OF WELLINGTON, COLORADO, a statutory municipality (the “Town”), collectively referred to as the “Members”. WITNESSETH: WHEREAS, the Members entered into the Intergovernmental Agreement for Stormwater Cooperation and Management on August 20 th , 2008 (the “IGA”) for the purpose of creating the Boxelder Basin Regional Stormwater Authority (the “Authority”); and WHEREAS, the Authority has, pursuant to the Boxelder Creek Regional Stormwater Master Plan dated October 2006 (“Master Plan”), proceeded to construct and complete the Coal Creek Flood Mitigation Project; and WHEREAS, the Authority has determined that two remaining projects are necessary to meet the flood mitigation and drainage goals of the Master Plan; and WHEREAS, the Authority has preliminarily designed the East Side Detention Facility also known as the Gray Lakes Project and the Larimer/Weld County Crossing Structure (the “Projects”) which are the two projects the Authority has determined need to be constructed to meet the goals of the Master Plan; and WHEREAS, the Authority has determined, through preliminary design, that the cost of the Projects is estimated at $9.9 million; and WHEREAS, the Authority has entered into an Intergovernmental Agreement dated November 15, 2012, (the “Timnath IGA”) between the Authority and the Timnath Development Authority of Colorado (“TDA”) which provides that TDA shall participate in the funding of the Projects; and WHEREAS, pursuant to the Timnath IGA, the TDA has transferred $500,000 to the Authority for use by the Authority in the continuing design of the Projects; and WHEREAS, pursuant to the Timnath IGA, the TDA will reimburse the Authority for 25% of the costs of the Projects incurred after the transfer of the $500,000 to the Authority; and EXHIBIT A WHEREAS, the Authority has determined the most cost efficient method of funding the Projects is obtaining a loan through the Colorado Water Conservation Bo0ard (“CWCB”); and WHEREAS, the CWCB loan requires a 10% local match resulting in a $9.0 million loan. This match will be the responsibility of the Authority with TDA reimbursing the Authority 25% of the match pursuant to the Timnath IGA; and WHEREAS, the Authority has met with the Members and reviewed the design and construction of the Projects, the funding of the Projects, and the terms and conditions of the proposed loan from CWCB; and WHEREAS, the Authority has requested the Members amend the IGA to allow the Authority to move forward with the funding and construction of the Projects; and WHEREAS, upon completion of the Projects, payment of all debt incurred by the Authority for the construction of the Projects, and agreement among the Members as to any continuing obligation for operation and maintenance of any Authority projects, there is no longer any need to continue with the Authority; and WHEREAS, the Authority and the Members have also determined that the Authority should have the right to make minor revisions to properties within the Service Area of the Authority by designating areas as “non-tributary areas”, and grant fee credits to other areas within the Service Area; and WHEREAS, the Members have determined to enter into this First Amendment in order to address the funding and construction of the Projects, the granting to the Authority the right to provide fee credits to appropriate properties within the Service Area, and the termination of the Authority. NOW, THEREFORE, in consideration of the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Members hereto agree as follows: 1. Article II of the IGA shall be amended by the addition of Section 2.10 to read as follows: Section 2.10 Service Area Revisions. The Authority shall have the authority to make minor revisions to the Service Area by designating properties as “Non- Tributary Properties” or grant fee credits to other properties within the Service Area as follows: (a) The Authority may, on a case by case basis, determine that individual properties in the Service Area are not tributary to the Boxelder Basin; and based upon that determination, remove those properties from the Service Area of the Authority. Any such removal shall be communicated to the Members in order for the individual Member to make appropriate adjustment in its fee structure. (b) The Authority may designate areas in the Service Area as “100 percent fee credit” properties based upon the following criteria: 1. There are properties located within the Service Area which as of the date of this Amendment drain into Soil Conservation Service/Natural Resources Conservation Service dam-impounded lakes and decreed irrigation reservoirs that in 100 year storm event release upstream waters at a rate less than or equal to the release from an historic two-year storm event. This effectively provides mitigation of downstream flood damage. These properties are eligible for 100% fee credit on the annual stormwater service fee as long as these conditions continue. 2. If a residential (dwelling) or commercial structure lies within a sub-basin area that drains to a lake, pond and/or depressed feature, which does not contribute runoff to the Boxelder Basin during a 100 year storm, the sub-basin shall be considered to be a non-tributary sub-basin and the individual property containing the residence (dwelling) or commercial structure is eligible for 100% fee credit on the annual stormwater service fee as long as the conditions do not change. The criteria for the Authority’s determination of such a sub-basin area being a non-tributary sub-basin is set forth on Exhibit A attached hereto and incorporated herein by reference. (c) If the Service Area boundary intersects any portion of a residential (dwelling) structure, then the property upon which the residence is located shall be assessed 50% of the annual stormwater service fee. (d) All fee credits shall be given on a calendar year basis. The Authority shall provide each individual Member with the 100% fee credit and 50% assessed properties located within each Member’s jurisdiction for the purpose of allowing the Member to calculate credits for any properties entitled to fee credits. 2. The IGA shall be amended by the addition of the following two Articles: ARTICLE IX EAST SIDE DETENTION FACILITY/GRAY LAKES AND LARIMER/WELD COUNTY CANAL CROSSING STRUCTURE PROJECTS FUNDING. Section 9.01 The Members hereby agree to authorize the Authority to apply for and receive a loan from the Colorado Water Conservation Board for the design and construction of the Projects upon the following terms and conditions: (a) The amount of the loan from the CWCB shall not exceed the principal sum of $9 million. (b) The Authority shall be responsible for the local match which is 10% of the principal sum of the loan. The 25% TDA reimbursement shall be part of the local match. (c) The term of the loan shall not exceed fifteen (15) years. (d) The interest rate on the loan shall not exceed 2.75% APR. (e) The Members shall provide any documentation or authority required by the CWCB of the Members for the Authority to obtain and this loan. ARTICLE X TERMINATION OF STORMWATER FEES AND CHARGES Section 10.01 The Members agree that the Authority shall terminate collection of stormwater fees and charges twenty years after the effective date of this Amendment provided there is agreement among the Members with regard to any continued obligation of the Authority which extends beyond such termination for operation and maintenance responsibilities for the Coal Creek Flood Mitigation, the East Side Detention Facility /Gray Lakes, and Larimer/Weld County Canal Crossing Structure projects, OR upon the occurrence of all of the following contingencies (a) through (e), whichever first occurs. (a) Completion of the East Side Detention Facility/Gray Lakes and Larimer/Weld County Canal Crossing Structure projects. (b) Payment in full of the loan from the CWCB and any other obligations of the Authority. (c) Agreement among the Members with regard to any continued obligation of the Authority which extends beyond the termination of collection of fees and charges by the Authority including, but not limited to, operation and maintenance responsibilities for the Coal Creek Flood Mitigation, the East Side Detention Facility/Gray Lakes, and Larimer/Weld County Canal Crossing Structure projects. (d) Agreement among the Members as to payment of any Authority obligation to the Members for matching funds of the Members for the FEMA Pre-Disaster Mitigation Grant in the approximate amount of one million dollars ($1,000,000). (e) Agreement among the Members as to the disbursement of any revenues of the Authority which remain after the Authority has finalized all of the administrative and organizational requirements necessary to terminate collection of fees and charges by the Authority including, but not limited to, any required budgets, audits, and filings with any state or federal authority. 3. This Amendment shall be effective upon the execution of the First Amendment by all of the Members. BOARD OF COUNTY COMMISSIONERS OF LARIMER COUNTY, COLORADO By: _______________________________________ Chair ATTEST: ____________________________________ Deputy Clerk to the Board Date: ___________________ Approved as to form: _________________________ County Attorney THE CITY OF FORT COLLINS, COLROADO A Municipal Corporation By: _______________________________________ Mayor ATTEST: ____________________________________ City Clerk Date: ___________________ Approved as to form: _________________________ City Attorney THE TOWN OF WELLINGTON, COLORADO A Statutory Municipality By: _______________________________________ Mayor ATTEST: ____________________________________ Town Clerk Date: ___________________ Approved as to form: _________________________ Town Attorney EXHIBIT A Policy for Non-Tributary Sub-Basin: If a residential (dwelling) or commercial structure lies within a Sub-Basin area that drains to a lake, pond and/or a depressed feature that can be shown to not contribute runoff to the Boxelder Basin during a 100-year storm, then the Sub-Basin will be considered to be a Non-Tributary Sub- Basin and the owner of the residential (dwelling) or commercial structure will be given a 100% fee credit on the annual stormwater service fee as long as the conditions don’t change. Option A: The following method can be used to determine if the Sub-Basin area in question is a Non-Tributary Sub-Basin: Step 1: Determine the entire drainage area for the basin, using the best available topographic data. Step 2: Determine the percent impervious area for the entire drainage area based on best available aerial imagery. Using Table RO-5 in Volume 1 of the Urban Storm Drainage Criteria Manual determine the associated ‘C’ value for Type C and D soils (Table attached). Step 3: Using the Rational Method Formula: Q=ciA Determine the volume of runoff for the closed basin area assuming a 2-hour design storm with a total depth of 3.67 inches. Multiply the volume by 2 to account for prior rainfall events. Step 4: Determine the volume of storage available within the pond, lake or depressed area being sure to account for the normal water surface elevation if there is one. Step 5: Compare the volume of runoff with the volume of storage available. If the volume of runoff is less than the volume of storage then the basin is a Non-Tributary Sub-Basin. Option B: The property owner can hire an engineer to prepare a ModSWMM computer model of the basin and storage area and prove through modeling that the basin is Non-Tributary. The Authority may require a property receiving a fee credit draining to a Non-Tributary Sub- Basin to provide a legal easement which permanently dedicates the available storage volume for stormwater management purposes.