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HomeMy WebLinkAboutJ_Conditional_Use_and_Variance_Justification_241007_v1Conditional Use Permit and Variance Justification for Buil ADU Location:5424 NE 10th St,Renton,WA Date:10/07/2024 Overview: The proposed project involves the construction of a 968-square-foot Accessory Dwelling Unit (ADU)on a residential lot located at 5424 NE 10th St.Due to the existing geography of the site, the ADU is proposed to be located within a designated wetland buffer.Additionally,a variance is requested regarding Renton’s setback requirement that stipulates the ADU’s front facade must be set back an additional 5 feet parallel to the primary residence's front facade.Due to site constraints,meeting this requirement would place the ADU closer to the wetland,which we aim to avoid. This justification addresses both the conditional use of building within the wetland buffer and the requested variance for the front facade setback. Site Conditions and Constraints: The subject property is characterized by sloped topography and a delineated wetland (Honey Creek)that occupies a significant portion of the lot.The 150 buffer extends beyond the property line in all directions.Alternative locations for the ADU were considered but were found to be either infeasible or would result in more significant environmental disturbance.The proposed ADU location was selected to minimize site disruption while still adhering to local zoning codes and setbacks where possible. Conditional Use Justification:ADU Within Wetland Buffer The necessity to place the ADU within the wetland buffer stems from the following factors: 1.Topographical Constraints:The steep slopes and natural geography of the lot limit buildable areas.The flat and accessible portions of the lot are located within the buffer, making it the only practical location for an ADU without significant grading or earthwork, which would cause greater environmental impact. 2.Existing Primary Residence Location:The current location of the primary residence, which predates current wetland regulations,precludes placing the ADU any further from the wetland boundary.Relocating the ADU any further from the wetland would involve demolition or extensive modifications to the existing home and would cause more disturbance than the proposed location. 3.Minimal Impact on Wetland Functionality:The ADU design and site plan prioritize minimizing disturbance to the wetland and its buffer.The structure will be sited on the periphery of the buffer,away from the most sensitive areas.Additionally,the proposed build site provides easy access from the street for construction equipment and personnel,thus avoiding any direct wetland encroachment.Furthermore,mitigation strategies will be employed as needed to ensure no net loss of wetland function.The small footprint of the ADU and removal of a second non-conforming driveway on the property ensures the impact on the buffer zone remains limited and contained,and total impervious service is actually reduced. Mitigation and Environmental Protection Measures: To address any potential environmental impacts,the following mitigation strategies will be implemented: 1.Erosion Control and Sediment Management:Best Management Practices (BMPs) such as silt fencing,erosion control blankets,and temporary sediment ponds will be utilized during construction to prevent sediment from entering the wetland area.A construction management plan will be in place to ensure compliance. 2.Minimizing Disturbance:Construction activities will be confined to a defined area,and heavy equipment will be limited to zones outside the most sensitive parts of the buffer. Vegetation removal will be minimized,and any impacted areas will be restored with native species post-construction. 3.Stormwater Management:A low-impact development (LID)strategy will be used to manage stormwater on-site.The ADU will be built on the site of an existing 4.Wetland Buffer Enhancement:As part of the mitigation plan,buffer enhancement activities such as planting native vegetation,removing invasive species,and improving habitat functions will be undertaken.This will offset the impact of placing the ADU within the buffer and result in a net ecological gain. 5.Long-term Monitoring and Maintenance:A long-term wetland buffer monitoring and maintenance plan will be established to ensure the buffer remains functional and healthy post-construction. Compliance with City of Renton’s Conditional Use Criteria: In accordance with Renton’s conditional use permit requirements,this project will: 1.Be Consistent with the Comprehensive Plan:The ADU aligns with Renton’s comprehensive plan,promoting housing diversity and infill development while prioritizing sustainable growth. 2.Minimize Environmental Impact:By employing BMPs and mitigation measures,the project will avoid significant adverse environmental impacts,protecting wetland functions and values to the maximum extent feasible. 3.Support Public Interest:The project serves a public interest by providing additional housing in an area where development opportunities are limited.Furthermore,the mitigation plan will improve wetland buffer quality over time. 4.Not Detract from Public Health,Safety,or Welfare:The ADU will be constructed with consideration for flood control,water quality,and habitat preservation.No detriments to public health,safety,or welfare will arise from this project. Variance Justification:ADU Front Facade Setback Variance Request: Renton’s building code requires the ADU’s front facade to be set back an additional 5 feet behind the front facade of the primary residence.However,complying with this requirement would force the ADU to be placed closer to the wetland,creating additional environmental impact.The proposed ADU location adheres to the general setback requirement that the ADU must be at least 30 feet from the street,while also maximizing the distance from the wetland buffer. Justification for Variance: The variance is necessary due to the unique geography of the property and the need to balance compliance with both the building code and environmental protection requirements.Key points of justification include: 1.Topographical and Environmental Constraints:The property’s geography,including sloped terrain and the presence of a wetland buffer,limits the space available for construction.Complying with the additional 5-foot setback would place the ADU in a location that encroaches further into the wetland buffer,increasing the environmental impact.By positioning the ADU as proposed,the structure remains as far from the wetland as possible while still complying with other setback requirements,such as the 30-foot distance from the street. 2.Minimum Necessary Relief:The requested variance is the minimum necessary to balance compliance with Renton’s setback and environmental regulations.The ADU is positioned to align with the intent of the setback rule,which is to ensure that accessory units are appropriately distanced from the street and primary structure.However,strict adherence to the additional 5-foot setback would create greater harm by increasing disturbance to the wetland buffer. 3.No Detriment to Public Interest or Neighboring Properties:The proposed ADU location will not cause any detriment to neighboring properties or the public interest.The structure’s placement is in keeping with the character of the neighborhood,and the ADU will be screened with landscaping to maintain privacy and aesthetic continuity. Furthermore,this variance request ensures that the environmental health of the wetland buffer is prioritized,which aligns with broader public interest in preserving natural resources. 4.Maintaining Consistency with City Goals:The ADU construction aligns with Renton’s broader goals of increasing housing diversity,providing additional affordable housing options,and encouraging infill development.Granting the variance allows the property owner to make reasonable use of the land without causing unnecessary harm to the environment,consistent with the city’s vision for sustainable development. Conclusion: This application seeks approval for both a conditional use permit to allow for the construction of an ADU within a wetland buffer and a variance to the front facade setback requirement.The property’s topographical constraints and the location of the wetland make strict compliance with these regulations impractical and environmentally harmful.The proposed location of the ADU represents the least impactful option for both the wetland and the surrounding environment, while still adhering to other setback requirements and minimizing neighborhood impact. With the implementation of comprehensive mitigation and environmental protection measures, this project will result in minimal ecological disruption and provide a valuable addition to the property and the Renton community.The requested variance is consistent with the intent of the code and ensures that the development of the ADU can proceed without increasing adverse environmental or neighborhood effects.