Middle Housing fourplexes in accordance with the State's Large Cities Middle Housing <br />Model Code, which was included as Exhibit B to OAR 660-046-0010. <br />Based on the applicant's argument and evidence from the second open record period (which is <br />now included in the record and hereby considered), and the applicant's subsequent appeal <br />testimony suggesting modification to this condition based on that evidence from the applicant's <br />engineer, Planning Commission finds that the above conditions should be modified. <br />As explained by the applicant's engineer in their letter dated August 14, 2024, a shared <br />stormwater system would be provided for the full build out of the project assuming a single -unit <br />dwelling on each lot, and the shared driveways are assumed to be impervious and would be <br />included in the shared detention facilities, to handle detention of a 10-year storm. Based on this <br />design, if a lot is developed with under 20% impervious surface area, no on -site detention would <br />be required, and if the lot has more than 20% impervious surface area then on -site detention <br />would be required. They explain that the detention facility must be sized by an engineer so that <br />peak flow from the lot does not exceed the peak flow generated by a 20% impervious area. <br />Furthermore, that the peak flow based on a 10-year storm event should be assumed at 2.1 cubic <br />feet per second per acre, based on site conditions. They recommend that any on -site detention <br />system should be designed by a civil engineer to meet applicable City standards. <br />Planning Commission finds that the updated stormwater report partially satisfies the above <br />condition of approval as it demonstrates the conceptual feasibility of a proposed stormwater <br />detention system, but to ensure compliance with the assumptions provided, and because Randy <br />Lane will be required to be constructed as a public street, the following (revised) conditions of <br />approval should be imposed instead: <br />Prior to final PUD approval, the applicant shall submit an updated site plan that includes <br />the following notes: <br />• "The approved stormwater system shall be designed and sized by a civil engineer for <br />the full build -out of the project to handle a 10-year design storm, including 20% of each <br />lot assumed to be impervious surface area. If a lot is proposed to be developed with <br />more than 20% impervious surface area, then additional on -site detention is required. <br />Stormwater runoff from private facilities may also be combined with runoff from the <br />public street (Randy Lane), so long as the public detention system is sized and designed <br />in accordance with applicable Public Improvement Design Standards." <br />• "In addition to the on -site detention requirements noted above, all subsequent site <br />development permits, building permits, and Privately Engineered Public Improvement <br />(PEPI) permits for development of the PUD shall demonstrate compliance with <br />applicable stormwater standards at EC 9.6791 through 9.6797 and requirements of the <br />Stormwater Management Manual." <br />These revised conditions provide more specificity about the required stormwater detention for <br />the proposed development, and account for the associated changes based on the requirement <br />that Randy Lane be constructed as a public street. These revised conditions are also appropriate in <br />Final Order: Braewood Hills 3rd Addition (PDT 24-1 and ST 24-3) Page 27 <br />