Loading...
HomeMy WebLinkAboutA026 - September 8, 2026, Regular Meeting of the Ames City CouncilITEM #:26 DATE:09-08-26 DEPT:P&H SUBJECT:AMENDMENT TO MASTER PLAN FOR HAYDEN PRESERVE (FOREMERLY ROSE PRAIRIE) AND REZONING OF A PORTION OF THE SITE TO FLOATING SUBURBAN RESIDENTIAL LOW DENSITY (FS-RL) AT 5571 HYDE AVENUE COUNCIL ACTION FORM BACKGROUND: Hayden's Preserve LLC owns a 170-acre site at the corner of Hyde Avenue and 190th Street (Attachment A - Location and Zoning Map). This site was originally planned for annexation with a development agreement in 2010 and the project was named Rose Prairie. Since that initial plan and agreement, two rezonings and amended Master Plans have been approved by the City and the project is now named Hayden’s Preserve. The most recent rezoning and Master Plan approval was in 2021 (see attached) and included an amended development agreement addressing certain off-site and on site improvement requirements. The current proposal is the result of recent changes to the City’s Conservation Subdivision Ordinance that modified allowable site design options and the City Council’s support for housing development incentives. The applicant describes the changes in detail with their attached project description. The most significant differences from 2021 to the current proposal include: Expansion of the FS-RL zoning Elimination of approximately 13.5 acres of FS-RM zoning and related apartment building units Reduction of the Commercial General Service (CGS) zoning from approximately 5 acres to 2.76 acres Modifications to the planning of open space and the set asides Creation of a new east west roadway across the creek connecting the internal collector street to Hyde Avenue Modification to the internal circulation of a "spine road" With this proposal, the total number of dwellings increase from a maximum of 620 to 675 dwelling units. The previous range was from 451 to 620 units. The new maximum range is from 350 units to 675. The proposed plan does not include a breakdown of planned unit types between attached and detached units as was provided with the prior plan. The prior 620 dwelling unit limit was set as part of the 2016 rezoning approval which was agreed upon in response to the developer ’s request to accommodate a maximum of 746 dwelling units. The 2021 Master Plan did not change the maximum number of units. The estimated overall developable area of the site has been relatively consistent between approximately 93 to 100 acres with all of the approved Master Plans and this proposal. 1 Based upon the estimated net 93 residential developable acres, the density is calculated at 7.25 dwelling units per net acre. The 2021 plan density for the combined FS-RL and FS-RM was 90.3 developable acres for a density of 6.9 dwelling units per acre. The proposed development density is within the allowable maximums of the FS-RL zoning, which is 10 dwelling units per acre. The housing types are now focused on single-family detached and attached housing without apartments or commercial office space. To achieve the high end of the dwelling unit targets, the project will include a substantial number of moderately sized single family detached lots and small detached single-family lots and townhome single- family attached lots. Some of the development will include townhomes for rent along with the majority of units planned as ownership housing. The developer anticipates applying for Planned Unit Development (PUD) approvals with future subdivision plans to accomplish this goal for a higher-density mix of single-family home types. Major issues from the prior Master Plan and rezoning applications included removing the planned east-west road connection, shared use path/trail construction, the amount of impervious area and the design of storm water treatment facilities in relation to the Ada Hayden watershed, and increased traffic. The proposed Master Plan once again includes the east-west roadway that was originally expected with the development. This is a significant and positive change to the overall plan that is tied to the City Council support for development incentives for the project. The Master Plan accommodates a major greenway for a recreation trail through the middle of the site. The developer will also include internal shared use path improvements. The City has determined that, as a development incentive, the Hyde Avenue trail will be built by the City and not the developer. The total open space is similar to prior plans and keeps both existing streams intact with offline (outside the current channel) stormwater treatment. At the time of subdivision review, details of storm water treatment and detention will be addressed. The developer intends to incorporate a treatment train approach to storm water that was previously agreed upon with approvals based upon the 2021 Master Plan. The Plan will include a neighborhood park of approximately five acres, subject to City Parks and Recreation staff approval regarding its final location and layout. The proposed plan has it shown in the west central part of the site. The prior plan had the park located further north, which by phasing would be completed sooner in the project. Staff supports a location to the north of the east-west waterway and will continue to refine its location and features prior to subdivision review. The current agreement requires dedication of the parkland to the City as part of an early phase of development. The City will then make park improvements at its discretion in the future. Trip generation from the increase in units was not determined to be a substantive change to the previous maximum of 620 units. The traffic generation and trip patterns are consistent with prior traffic analysis and assumptions for growth in this area, most recently with the Ames Plan 2040 Comprehensive Plan, 190th Street roundabout study, and the most recent Ames Area 2 MPO transportation plan adopted in 2025, Ames Connect 2050. At the time of subdivision review, appropriate turn lane improvements along Hyde and 190th Street will be evaluated. No additional dedication of land or improvements by the developer are anticipated at this time in relation to 190th/Hyde intersection. A Master Plan is a City of Ames requirement for development of FS-RL areas of the City. A Master Plan defines basic layout and use issues of a site as part of a rezoning action. The Master Plan is required to identify types of uses, density, natural areas, and perimeter road and trail access points. A Master Plan does not approve a subdivision of the land and internal lot layouts, only the range of use. Prior to grading of the site or construction of buildings, a subdivision would need to be approved to provide the detail needed to verify consistency with City standards related to lot layouts, road pattens, and utility extensions. Subsequent development must conform to the Master Plan and a subdivision plat is reviewed for consistency with the Master Plan. As noted earlier, the proposed Master Plan identifies the planned development areas of the site and the primary street connections. The Plan allows for detached and attached single-family housing, but does not estimate the quantities of each type of housing. The proposed Master Plan differs from the 2021 Plan in its designation of areas for development and housing details. The proposed Master Plan does not identify separate “pods” of development as was provided with the prior Master Plan. The core area of the plan is intended for concentrated residential development and an interconnected street system compared to the last concept of a central spine road and loop streets. Some open spaces will be included within this core area, but it is not a defined open space element as it was with the prior Master Plan with the pods. This is partially a result of the changes to the Conservation Subdivision Ordinance requirements related to site layout. However, staff finds the overall open space plan to be consistent with prior points of emphasis regarding creek buffers and managing stormwater runoff to protect Ada Hayden. DEVELOPMENT AGREEMENT The current development agreement is a combination of terms from the original pre- annexation agreement, 2016 master plan amendment, and the revised plans from 2021. The agreement addressed layout, payment of the Hyde Avenue street assessment, payment of traffic, water, and sewer fees, construction of the shared use path, phasing, extension of the east-west trunk line sewer, and the public park dedication. In December 2025, City Council indicated support for development incentives related to housing construction and addressed the developer's request by indicating support to change the development agreement and to substantially modify the terms. As a result, a wholly new development agreement will be drafted for the project that reflects Council's direction regarding incentives and the proposed Master Plan. The developer indicated to staff that they decided to proceed with this project because of these Council incentives and the benefit of the reduced Xenia water territory buyout fee. They have requested consideration of one change from December tied to the cost of culvert crossing. The developer asks that the Council support $750,000 of the culvert construction 3 costs with use of a TIF rebate. Staff has not reviewed details of this cost in comparison to the initial phase of development costs and will explore it in greater detail. Staff had originally proposed 50% of the cost (est. $375,000) along with corresponding requirements for LMI set- asides that not longer apply. Staff believes this connection is vital and needs to be part of the initial phase of development. Staff believes that if their is justification to increase the amount to the requested $750,000, it can be accommodated within the original parameters of skipping an initial year of TIF payment to account for General Fund growth and then still make rebate payments to the developer to pay off the improvement within 5-10 years. It will be very important to limit the amount of area in the TIF to preserve general fud growth. Staff does not support any structure of rebates that extends past ten years because the intent is to incentivize housing production as soon as possible and put the onus on the developer to produce housing. Therefore, the structure of rebate in the future agreement will be tied to phasing and accounting for a TIF rebate payment to maximize the benefit of general fund property tax growth. The new agreement will address the phasing of the project and the timing of the construction of the culvert and cross of the creek as well as the remaining developer obligations. The following is a list of the other substantial incentive issues and developer obligations: The City will waive the traffic signal fee The City will waive water and sewer connection fees for the initial phase(s) of platted lots in the first three years (up to 215 dwellings). The City will undertake the extension of the east west trunk sewer, the Developer will then extend utilities through the site and connect to the trunk line. The Developer will dedicate a neighborhood park to the City's specifications. The Developer will plan for the east west greenway trail connection. The City will construct the Hyde Avenue shared use path. The Developer is responsible for street turn lane improvements and all improvements within the subdivision. PUBLIC NOTICE Prior to the Planning and Zoning Commission meeting on August 19th, 400 foot mailed notice was sent to property owners and a sign was placed upon the site. Staff received one written comment about concerns with the project that was also discussed in person at the P&Z meeting. The concerns included the history of traffic studies and new turn lane requirements, potential impacts to water quality, questions about the need and benefit of increasing density, grading plans, and housing types of the project. One other member of the public spoke asking when more details would be available with the future preliminary plat application. Staff discussed the history of the traffic analysis and conditions that were modeled for 190th and Hyde Avenue and that the increase in proposed units did not trigger a new analysis. Future improvements to Hyde south of this site are part of the City's CIP. The design of turn lanes for the project would be part of the preliminary plat process. Issues of stormwater were part of the open space planning and impervious surface estimates provided by the applicant, staff believes there will be a benefit to water quality with development compared to row crops. However, the formal stormwater management plans review is part of the preliminary plat. 4 The Commission explored questions about the creek, flood plain location, future stormwater treatment, the requirements and tradeoffs of the Conservation Subdivision Ordinance, housing types including changes to apartments, and the general layout of the site. The Commission voted 7-0 to recommend approval. ALTERNATIVES: 1. The City Council can: a. Approve the request for the amendment to the Master Plan with first reading of an ordinance for rezoning of the site to FS-RL as shown with the attached Master Plan and retain approximately 2.76 acres of CGS zoning, subject to a zoning agreement for the Master Plan prior to third reading for approval of the rezoning request. b. Approve a motion directing staff to work with the Developer to address the housing incentives and development agreement terms included within this report. 2. The City Council can make modifications to the described the Master Plan regarding the housing unit counts or layout and approve on first reading an ordinance rezoning the site and for an updated Master Plan and zoning agreement prior to third reading or direct staff to makes changes to the proposed development agreement terms. 3. The City Council deny the request for an amendment and rezoning to FS-RL if the change is not consistent the Ames Plan 2040, is not in the public interest, or other policies and regulations of the City. 4. The City Council can defer action on this request and refer it back to City staff and/or the applicant for additional information. CITY MANAGER'S RECOMMENDED ACTION: The proposed Master Plan and rezoning is a different approach to the development of the site that focuses on single-family attached and detached housing compared to the prior mix of zoning and housing types. The developer has struggled to develop the site within the constraints of the site conditions and infrastructure costs since acquiring the site. The developer formulated this plan as response the City Council’s support for development incentives that lessen the infrastructure burdens for the developer. Even with incentives, the developer will bring utilities into the site and extend them through the site at their cost. Roadway improvements are also a developer cost. The culvert crossing of the creek for the east west road connection is an incentivized piece of infrastructure to be built by the developer, but intended for the developer to be reimbursed for this investment. Removing the crossing as a cost savings was contentious during the 2016 Master Plan and 2021 Master Plan. Staff believes the inclusion of the east west roadway is a significant enhancement to the overall project design. Staff also believes this is the most critical element of the amendment because it improves overall connectivity and constructability of the project by being able to support phasing from the middle of the site instead of from 190th. 5 The housing mix can be found consistent with RN-3 land use designation and goals from the Land Use and Growth and Neighborhood, Housing, and Subarea Elements related to supporting additional ownership housing and variety of housing choice even though the apartment component is removed from the plan. There will still be rental townhome component of the project. The proposed increase in total housing units is at the upper end of projected housing density for this size and type of site. In 2016 the Developer had asked for substantially more units and was eventually limited to 620 to address development intensity concerns. At that time staff had estimated approximately 650 units would be consistent with development patterns that would also address site and layout concerns. Based upon the Master Plan layout and staff’s preliminary review of development concepts, the proposed maximum of 675 units can fit within the constraints of the site. Therefore, it is the recommendation of the City Manager that the City Council adopted Alternative No. 1. ATTACHMENT(S): Addendum with Location Map.docx Applicant Narrative Haydens Preserve Impervious Area Comparison Hayden's Preserve Master Plan.pdf 5571 Hyde Ave-Hayden's Preserve- Rezoning Ord.docx 6 1 ADDENDUM Ames Plan 2040. Since the prior approvals for the site, the City updated its comprehensive plan to Ames Plan 2040. The site was previously considered Suburban Residential with a Neighborhood Commercial Node. The previous plans conformed to these designations and related policies. Plan 2040 identifies the site as RN-3 with a component of Neighborhood Commercial Mixed Use. The site also includes an Open Space designation related to the planned park. The current designations largely follow the general development approac h of the prior designations. Both the prior Master Plan and the proposed amendments conform to the Land Use and Growth policies for RN-3. See excerpts of relevant land use and housing policies from Plan 2040 below. AMES PLAN 2040 LAND USE MAP EXCERPT Plan 2040 includes Park, Trails, Greenways Element. The project proposal includes a plan for area dedicated as a public park to meet policies of the Element related to 5 acres of parkland per 1,000 people and having a park located within ½ mile of the development. The combination of new parkland within the project and proximity to Ada Hayden meet these standards. The Master Plan also include the planned east west greenway that the City aspires to connect to the west to Greenbriar and GW Carver Avenue. Subject Site 190th St 7 2 RN-3 EXCERPT FROM AMES PLAN 2040-PAGE 55 8 3 HOUSING ELEMENT EXCERPT FROM AMES PLAN 2040-PAGE 111 Existing/Proposed Zoning. The proposed rezoning changes approximately 13.5 acres of FS-RM and 2.75 acres of CGS to FS-RL zoning. This changes the allowable uses within these areas from apartments and commercial to single-family detached and attached housing. The overall density range of the proposal is within the minimum and maximum density ranges of 3.75 to 10.0 dwelling units per net acre. The initial zoning of FS-RM and CGS was at the request of the applicant rather than a land use requirements of the prior Comprehensive Plan. Staff does not find that commercial area on this site is essential to meet any specific service needs of the City. A small commercial area remains along Hyde/190th and that maintains consistency with the current Plan 2040 designation for the corner. A C -store gas station is the likely long term use of that location. Additionally, since 2016 the City has added planned commercial area to the west with the planned Greenbriar project. The current FS-RM zoning was also requested by the developer in order to construct apartments and develop a large portion of the site all at one time to improve the financial aspects of the project. Staff originally supported a limited number of apartments to provide housing diversity with north growth. The developer will likely have a larger rental development component within the project using a townhome concept rather than apartments. Townhome rentals provide some diversity of use, but not at the same level as apartments in terms of affordability. 9 4 The Master Plan indicates that more than 10% of the site will be set aside for Open Space as required by FS-RL zoning, nearly 40 acres of area are planned for various types of open spaces set asides where a minimum of 17 is required. Storm Water Management. The site will be developed to meet the requirements of the City’s Conservation Subdivision Ordinance and Chapter 5b water quality and detention requirements. The major natural drainage features will be preserved based upon the Master Plan. The site previously had a natural resources survey approved by the City Public Works Department and the new proposal is consistent with the prior analysis. The standards require on-site treatment and storage of stormwater within open spaces and conservation areas. The 2021 Plan estimated that 27.6 percent of the gross site acres will be open space set asides. The current estimated open space is 23.5 percent. Additional open space, such as trail corridors and drainage swales may be identified during the preliminary plat process, increasing that number. The developer has also included an impervious surface calculation comparison of the prior master plan and the proposed master plan. These calculations are included as an attachment. Staff also notes that since 2016, FEMA remapped flood plains in Story County and the main channel that flows north south through the site is now labeled as a general flood plain, which makes it subject to local flood plain ordinance standards and jurisdictional review with state and federal agencies for changes to the channel. The Master Plan does not indicate how stormwater will be treated and stored in accordance with City requirements. However, the conservation subdivision regulations require buffers along drainage ways and encourage best management practices in treating storm water. In addition, the Chapter 5B Post-Construction Storm Water Management will apply as well. The specific stormwater treatment plan for the deve lopment will be evaluated as part of the preliminary plat review. 10 5 Attachment A: Location and Zoning Map 11 Memo| Hayden's Preserve Rezoning and Master Plan Narrative Page 1 Rezoning Request Narrative Date: August 13, 2026 Project: Hayden's Preserve | 5571 Hyde Avenue, Ames, Iowa To: Kelly Diekmann, Planning and Housing Director From: McClure, on behalf of Hayden's Preserve LLC / ATI Group Subject Rezoning and Master Plan Narrative Project Background and Purpose Hayden's Preserve is a 170.33-acre master-planned community legally described as Lot 2 of the Rose Prairie Final Plat. The property is bounded by Hyde Avenue and W 190th Street, with the railroad forming another site boundary. An unnamed tributary and its associated floodplain cross the property and establish a continuous open-space and stormwater-management corridor that has served as the organizing feature of each master plan concept. The requested rezoning and master plan amendment would revise the Council-approved 2021 plan, as reflected in the February 15, 2022 informal update. Portions of the existing commercial and FS-RM areas are proposed for FS-RL zoning, while the master plan intentionally retains flexibility in the ultimate allocation of the 93.07-acre residential developable area between FS-RL and FS-RM. Separate acreages for the two districts are therefore not fixed at this master-plan stage and would be established through subsequent detailed planning and platting. The principal goals are to expand the flexibility and supply of housing, simplify the land-use pattern, right-size the commercial component, improve internal and external connectivity, and coordinate development with the tributary corridor, open space, park area, and planned stormwater treatment areas. The resulting neighborhood is intended to accommodate attached and detached single-family housing through phased development supported by public streets, utilities, open-space amenities, and trail connections. The 2021 Approved Master Plan The prior master plan established three zoning districts: a 6.01-acre Convenience General Service (CGS) commercial area, 13.54 acres of FS-RM residential area, and 76.83 acres of FS-RL residential area. Within 90.37 net residential acres, the plan supported 451 to 620 dwelling units: 136 to 192 FS-RM units, 110 to 155 attached single-family units, and 205 to 273 detached single-family units. The 2021 plan allocated 23.10 acres to public right-of-way, 38.22 acres to dedicated open space, and 12.67 acres to a public-park area. Its street system used a north-south collector and local loops and cul-de-sacs, with connections to Hyde Avenue and W 190th Street. The 2021 amendment eliminated a previously contemplated east-west street connection from Hyde Avenue to the collector. Trails, stormwater treatment areas, and the generalized greenway corridor followed the site's drainage features. 12 Memo| Hayden's Preserve Rezoning and Master Plan Narrative Page 2 The Proposed 2026 Revision The proposed revision retains the 170.33-acre site boundary and reorganizes the development program into 93.07 acres of residential developable area, 21.52 acres of proposed public right-of-way, 39.96 acres of open space, a 2.76-acre commercial area, and 13.02 acres identified on the exhibit as 'Net Area.' The residential program increases to an estimated 650 to 675 units, or approximately 3.82 to 3.97 dwelling units per gross acre, and the residential area is labeled for attached and detached single-family housing. The revised circulation concept adds a continuous east-west street connection, provides three connections to Hyde Avenue and a connection to W 190th Street, and identifies a connection toward Auburn Trail. This connected framework replaces more isolated loop and cul-de-sac segments, distributes traffic among additional access points, and provides a clearer structure for emergency access, utilities, pedestrian movement, and phased construction. A future 10-foot shared-use path is identified along Hyde Avenue. The unnamed tributary and floodplain remain the central open-space spine. The exhibit also identifies a park area, open-space detention and buffer areas, conceptual water-quality treatment areas within the developable blocks, and onsite and offsite stormwater drainage outlets. These features continue the prior plan's approach of coordinating development with drainage and environmental corridors while adapting the developable blocks to the proposed residential program. Comparison to the Prior Master Plan The proposed master plan retains the same project boundary but revises the planned unit range, housing mix, street framework, open-space allocation, and zoning approach. The following comparison uses the February 15, 2022 informal update of the 2021 master plan and the proposed master plan exhibit submitted August 5, 2026. Topic Prior Master Plan Proposed 2026 Plan / Change Gross project area 170.33 acres 170.33 acres; no change Residential units 451-620 units 650-675 units; higher planned unit range Housing types FS-RM residential housing; FS-RL attached and detached single-family housing Attached and detached single-family housing Street configuration North-south collector and local loops/cul- de-sacs; no east-west connection from Hyde Avenue to the collector Adds a continuous east-west connection and a more connected internal street framework Vehicular access Connections to Hyde Avenue and W 190th Street Three Hyde Avenue connections, one W 190th Street connection, and a connection toward Auburn Trail Commercial 6.01 acres 2.76 acres; decrease of 3.25 acres FS-RM 13.54 acres Not separately allocated; included within the combined 93.07-acre residential developable area FS-RL 76.83 acres Not separately allocated; included within the combined 93.07-acre residential developable area Residential developable area 90.37 net acres 93.07 acres; increase of 2.70 acres 13 Memo| Hayden's Preserve Rezoning and Master Plan Narrative Page 3 Topic Prior Master Plan Proposed 2026 Plan / Change Proposed public right-of-way 23.10 acres 21.52 acres; decrease of 1.58 acres Open space / public park 50.89 acres total (38.22 acres dedicated open space plus 12.67-acre public-park area) 39.96 acres shown as open space, including park, detention, and buffer areas; decrease of 10.93 acres based on exhibit labels Other net area Not separately identified 13.02 acres identified as 'Net Area' Gross density Approximately 2.65-3.64 dwelling units per acre Approximately 3.82-3.97 dwelling units per acre Trail system Internal trail system and oversized greenbelt trail Future 10-foot shared-use path along Hyde Avenue and connection toward Auburn Trail Estimated impervious area 80.59 acres using the 2016 coefficient method 78.16 acres under stated assumptions; estimated decrease of 2.43 acres Support for the Requested Zoning Approach The requested zoning approach supports the City's purpose for the Suburban Residential Floating Zone by providing a contemporary suburban development pattern with coordinated residential land uses, an efficient street and utility framework, and planned open space. FS-RL accommodates the attached and detached single- family housing identified on the proposed master plan, while retaining FS-RM as a secondary designation preserves flexibility to respond to the final subdivision layout, housing program, and phasing. The master plan is intended to establish the overall development framework rather than fix the boundary or acreage of each residential zoning district. The combined 93.07-acre residential developable area, together with the planned unit range of 650 to 675 units, provides the controlling sitewide framework. The final FS-RL and FS- RM allocation would be established through subsequent rezoning, subdivision, and site-planning actions as development details are refined. The revised plan also advances the FS development principles by organizing developable areas around natural drainage corridors, reserving land for open space and stormwater treatment, and providing multiple street and trail connections. These features support an efficient and connected subdivision pattern while protecting environmental corridors and providing neighborhood amenities. Impervious Area Comparison A separate impervious-area and stormwater-volume worksheet accompanies this narrative. Using the same land-use coefficients and rainfall depths documented in the May 25, 2016 Rose Prairie calculation, the 2021 master plan is estimated at 80.59 acres of impervious area and the proposed 2026 master plan is estimated at 78.16 acres, a preliminary reduction of approximately 2.43 acres. The 2026 estimate assumes 9.00 acres of improved park based on the June 8, 2021 Council Action Form, treats the remaining 30.96 acres of the stated 39.96-acre open-space total as non-impervious, and applies 0% imperviousness to the separately identified 13.02-acre 'Net Area.' The estimate must be revised if the park acreage or intended use of the Net Area differs from those assumptions. 14 Memo| Hayden's Preserve Rezoning and Master Plan Narrative Page 4 Conclusion The proposed 2026 revision builds on the 2021 entitlement framework while updating the land-use pattern, residential program, and circulation network to support current development objectives. It preserves the 170.33-acre boundary and the tributary/open-space corridor, reduces the standalone commercial area, increases residential developable acreage and unit capacity, and restores an east-west street connection with additional site access. By intentionally leaving the FS-RL and FS-RM acreage split flexible within the combined residential area, the master plan provides a coordinated basis for phased development while allowing the final zoning allocation to respond to the detailed subdivision design and housing program. 15 (8.13.26) Usage Area (acres) Units or Lots % Impervious ⁵ Impervious Area (acres) Single Family (Detached)54.92 273 65% 35.70 Single Family (Attached)21.91 155 65% 14.24 Medium Density 13.54 192 65% 8.80 Commercial 6.01 - 85% 5.11 ROW 23.10 - 67% 15.48 Park 12.67 - 10% 1.27 Open Space 38.22 - 0% 0.00 Total 170.37 620 47% 80.59 Usage Area (acres) Units or Lots % Impervious ⁵ Impervious Area (acres) Residential Developable Area⁶93.07 675 65% 60.50 Commercial 2.76 - 85% 2.35 ROW (collector and local streets)⁷,⁹21.52 - 67% 14.42 Reserved Park 4.93 - 10% 0.49 Open Space (excluding reserved park)35.03 - 0% 0.00 Other Net Area 13.02 - 0% 0.00 Total 170.33 675 46% 77.75 1 Yr (acre-feet) 10 Yr (acre-feet) 100 Yr (acre-feet) Depth, in. (24 hour event) 2.67 4.46 7.12 2021 Master Plan 17.93 29.95 47.82 2026 Master Plan 17.30 28.90 46.13 Hayden's Preserve Master Plan - Impervious Area Stormwater Volume Calculations¹, Table 1: Impervious Area Calculations for 2021 Master Plan Table 2: Impervious Area Calculations for 2026 Master Plan Table 3: Stormwater Volume Calculations (on impervious areas only)¹,⁸ 16 V = CDA Where, V = Total Volume (acre-ft) C = Runoff coefficient D = Depth of rainfall (ft.) I = Area (acres) 6. The 2026 exhibit identifies one combined 93.07-acre residential developable area. The 65% residential coefficient is applied to the entire area, including the local/internal streets contained within the residential developable area. 7. The separately identified 21.52-acre ROW represents the broader ROW network, including collector and local streets—not collector roads only. It is retained at 67% impervious, based on a typical 60-foot ROW with 28 feet of paving and dual 6-foot sidewalks. 8. The 2026 exhibit identifies 39.96 acres of total open space. Of this area, 4.93 acres are reserved for park use and assigned 10% impervious; the remaining 35.03 acres and the separately identified 13.02-acre 'Net Area' are treated as 0% impervious. Future stormwater treatment facilities are not included. These calculations are preliminary and must be updated if those assumptions change. 1. Only calculates surface water runoff from impervious areas that are conservatively assumed. 2. 2021 areas and unit counts are based on the June 8, 2021 Council Action Form. Published land-use categories sum to 170.37 acres, 0.04 acre greater than the stated 170.33-acre gross site because of rounding. 3. 2021 maximum counts are 273 detached single-family units, 155 attached single-family units, and 192 medium-density units, for 620 total units. 4. The maximum unit count proposed in the 2026 Master Plan (675 units) is used for these calculations per City request. 5. SUDAS Table 2B-4.03 is used for percent impervious area by land use, consistent with the May 25, 2016 calculation. Footnotes: 17 18 DO NOT WRITE IN THE SPACE ABOVE THIS LINE, RESERVED FOR RECORDER Prepared by: Renee Hall City Clerk’s Office, 515 Clark Avenue, Ames, IA 50010 Phone: 515-239-5105 Return to: Ames City Clerk, P.O. Box 811, Ames, IA 50010 ORDINANCE NO. AN ORDINANCE AMENDING THE OFFICIAL ZONING MAP OF THE CITY OF AMES, IOWA, AS PROVIDED FOR IN SECTION 29.301 OF THE MUNICIPAL CODE OF THE CITY OF AMES, IOWA, BY CHANGING THE BOUNDARIES OF THE DISTRICTS ESTABLISHED AND SHOWN ON SAID MAP AS PROVIDED IN SECTION 29.1507 OF THE MUNICIPAL CODE OF THE CITY OF AMES, IOWA; REPEALING ALL ORDINANCES AND PARTS OF ORDINANCES IN CONFLICT HEREWITH AND ESTABLISHING AN EFFECTIVE DATE BE IT HEREBY ORDAINED by the City Council of the City of Ames, Iowa; Section 1: The Official Zoning Map of the City of Ames, Iowa, as provided for in Section 29.301 of the Municipal Code of the City of Ames, Iowa, is amended by changing the boundaries of the districts established and shown on said Map in the manner authorized by Section 29.1507 of the Municipal Code of the City of Ames, Iowa, as follows: That the real estate, generally located at Hayden’s Preserve Development at 5571 Hyde Avenue, is rezoned to Floating Suburban Residential Low (FS-RL) Density with Master Plan. Real Estate Description: for 5571 Hyde Avenue, Lot 2 of the Rose Prairie Final Plat, removing existing Floating Suburban Residential Medium Density (FS-RM) zoning while increasing the area of Low Density Residential (FS -RL) zoning to approximately 167 acres and reducing the Commercial General Service (CGS) zoning to approximately 3 acres of the site. Section 2: All other ordinances and parts of ordinances in conflict herewith are hereby repealed to the extent of such conflict. Section 3: This ordinance is in full force and effect from and after its adoption and publication as provided by law. ADOPTED THIS day of , . 19 Renee Hall, City Clerk John A Haila, Mayor 20