New High School 2501

ISD HS4-ES17 SEPA - Final Revised Reissued MDNS 01-17-2022

ISD HS4-ES17 SEPA - REISSUED SEPA Environmental Checklist 12-01-2021

ISD HS4-ES17 SEPA - Addendum to 01-17-2022 Final Revised MDNS

ISD HS4-ES17 SEPA - Appendix A1 Geotechnical Report 06-17-2021

ISD HS4-ES17 SEPA - Appendix A2 Landslide Hazard Assessment 09-24-2019

ISD HS4-ES17 SEPA - Appendix B1 Critical Area Study and Wetland Mitigation Plan 07-10-2020

ISD HS4-ES17 SEPA - Appendix B2 Updated Critical Area Study and Wetland Mitigation Plan 02-22-2021

ISD HS4-ES17 SEPA - Appendix B3 Addendum to Critical Area Study and Wetland Mitigation Plan 07-30-2021

ISD HS4-ES17 SEPA - Appendix B4 Stormwater System and Potential Impact to Laughing Jacobs Creek Letter 09-10-2021

ISD HS4-ES17 SEPA - Appendix B5 Technical Information Report 04-2021

ISD HS4-ES17 SEPA - Appendix B6 Preliminary Frontage Technical Information Report 03-2021

ISD HS4-ES17 SEPA - Appendix B7 Laughing Jacobs Creek Project Discharge Memo 09-07-2021

ISD HS4-ES17 SEPA - Appendix C1 Arborist Report Tree Evaluation and Retention Report 08-2020

ISD HS4-ES17 SEPA - Appendix C2 Updated Arborist Report Tree Evaluation and Retention Report 04-2021

ISD HS4-ES17 SEPA - Appendix D1 Water Tower Lead in Soil Screening Summary 03-03-2020

ISD HS4-ES17 SEPA - Appendix D2 Phase 1 Environmental Site Assessment 10-12-2021

ISD HS4-ES17 SEPA - Appendix E1 Noise Study 09-02-2020

ISD HS4-ES17 SEPA - Appendix E2 Noise Study Addendum 11-24-2021

ISD HS4-ES17 SEPA - Appendix E3 Football Field Acoustics Memo 11-24-2021

ISD HS4-ES17 SEPA - Appendix F COI SEPA Checklist for 2019 Annual Comp Plan & Zoning Map Amendments 08-28-2019

ISD HS4-ES17 SEPA - Appendix G1 Lighting System Review Summary 04-16-2021

ISD HS4-ES17 SEPA - Appendix G2 Exterior Lighting Memo 09-28-2021

ISD HS4-ES17 SEPA - Appendix G3 Athletic Field Lighting 11-12-2021

ISD HS4-ES17 SEPA - Appendix G4 Solar Access Analysis Memo 09-02-2021

ISD HS4-ES17 SEPA - Appendix H1 Revised Transportation Technical Report Final 02-16-2021

ISD HS4-ES17 SEPA - Appendix H2 Updated Traffic Analysis for 228th Ave SE Near the Site 05-18-2021

ISD HS4-ES17 SEPA - Appendix H3 Updated Traffic Analysis for Site Access Driveway 08-18-2021

ISD HS4-ES17 SEPA - Appendix H4 Sensitivity Analysis of School Boundary Changes 08-18-2021

ISD HS4-ES17 SEPA - Appendix H5 Technical Memorandum for Potential Traffic Calming Measures 06-10-2021

ISD HS4-ES17 SEPA - Appendix I Greenhouse Gas Emissions Worksheet 11-12-2021

General Project Questions and Answers

Content below updated March 23, 2026

1.  Why is a new high school still needed?

The Issaquah School District is committed to providing educational excellence that helps all students thrive and prepares them for life after graduation. High schools remain overcrowded, and even with projected reductions in elementary enrollment over the next five to ten years, existing facilities are not designed to safely accommodate current or future student populations. Planning for a new high school has been underway for more than a decade to address these needs while responsibly using local tax revenue, rather than relying on aging and overcrowded facilities that may not meet tomorrow’s needs. Modern, well-planned facilities ensure students are prepared for future learning, including pathways to higher education, careers and durable skills.

2.  How was the decision made to move forward with this project?

The decision to ask the community to fund a new high school was neither made in isolation nor rushed. Voters approved funding in 2016 and again in 2022 due to overcrowding of high schools. During the planning process, the district actively sought and considered input through public hearings, city meetings, School Board discussions, town halls, and multiple public comment periods. Feedback from families, neighbors, community members, agency staff, and elected officials was reviewed and considered at every stage.

The project required a rezone and comprehensive plan amendment as well as project-specific permits, and over time, was subject to administrative appeals and litigation led by a small group opposed to building a comprehensive high school at this site. At each stage, the district agreed to meet enhanced land and building design standards and provided voluntarily additional accommodations, above and beyond what would otherwise be required, to address comments from nearby residential communities, totaling nearly $16 million in added project costs. These adjustments reflect the district’s commitment to being a responsible neighbor.

Over time, project delays and market conditions contributed to increased construction costs from approximately $120 million in 2016 to $292.7 million in 2024. The district asked voters to consider additional funding through bonds proposed in 2024 and 2025, but both measures fell short of the required supermajority. Despite these challenges, the district remained committed to moving forward within its means to address continued overcrowding at existing high schools.

In April 2025, the School Board authorized a phasing concept to move forward initially with a reduced-size high school using voter-approved funds from 2016 and 2022. The current project cost estimate (New High School 2501) is $ 168.1 million, which includes $22.3 million of previously spent funds for project development, design and legal fees for litigation, real estate and agency reviews.

In November 2025, the City of Issaquah Development Commission, following a public review process, approved the additional project phasing. An appeal was filed to the City’s hearing examiner, with the appeal denied after review.  The City’s action on the permit amendment became final in late February 2026, allowing the project to proceed. Preconstruction activities are underway and construction is expected to begin in April 2026.

3.  How were environmental and regulatory factors evaluated for the project?

The district’s design and planning work was closely coordinated with required environmental review and permitting. This included evaluation under the State Environmental Policy Act (SEPA), as well as technical studies and agency review related to transportation, stormwater, land use and other environmental factors.

Feedback received through these processes informed project design, mitigation measures and final approvals. Multiple agencies and the public had opportunities to review and comment on the environmental analysis. This SEPA review ensured the project meets or exceeds state and local requirements and provides appropriate protections for the surrounding environment.

 The following questions below address key topics raised during the design and review process.

Transportation & Stormwater Questions and Answers

1.  Was a transportation analysis performed for the proposed school project and what was the City of Sammamish’s role in this analysis?

Heffron Transportation, Inc., a firm with more than 30 years of experience evaluating school projects throughout the Puget Sound region, was hired by the Issaquah School District to perform detailed transportation analysis for the proposed school project. The original Transportation Technical Report was subject to several rounds of agency review by both the City of Issaquah and City of Sammamish (including each City’s contracted transportation consultants). The Revised Transportation Technical Report (February 16, 2021) incorporated comments from both the City of Issaquah and the City of Sammamish, and was accompanied by a comment response matrix listing all city comments and how they were addressed. Key assumptions and findings from the Transportation Technical Report are:

• All analysis was performed for the Full Build condition, which includes an 1,823-student high school plus a 744-student elementary school.
   
• The study area for the transportation analysis covered 23 major intersections, 17 of which are in the City of Sammamish. Analysis was performed for the morning arrival, afternoon dismissal, and commuter PM peak hours to capture times when school traffic and commuter traffic would be highest at area intersections and along 228th Avenue SE. 
   
• Extensive analysis was performed for the 228th Avenue SE / SE 43rd Street corridor to determine the optimal configuration and traffic control to serve both the new schools as well as substantial increases in traffic associated with growth and development in the City of Sammamish. Options such as roundabouts, different lane configurations at the school access, and pedestrian crossing treatments were assessed. The final configuration recommended for the 228th Avenue SE frontage was based on that analysis.
   
• Extensive analysis was also performed for the SE 40th Street / 228th Avenue SE intersection to assess measures that would improve operations without attracting excess cut-through traffic on SE 40th Street. The recommended plan was based on that analysis. 
   
• On-site circulation and load/unload operations were also evaluated, with findings incorporated into the design of the internal site roadway system and student drop-off/pick-up areas. 
   
• Detailed parking analysis was performed to determine parking demand on typical school days and during different types of events. 
   
• Many mitigation measures were recommended in the Transportation Technical Report. All of the physical transportation improvements have been incorporated into the project plans. Additional measures were recommended to manage traffic and parking during construction and once the school is operational.

2. What if the school enrollment boundaries change in the future? 

School attendance boundaries are set by the Issaquah School Board, and any changes in boundaries would be subject to a Board review process. During the course of the traffic analysis described above the City of Sammamish staff raised questions about how any future changes in school boundaries could affect traffic conditions and whether it would change the recommended mitigation measures. To respond to those questions, a sensitivity analysis was performed and presented in a Technical Memorandum: Traffic Impact of School Boundary Changes (Heffron Transportation, Inc., August 18, 2021). 

The sensitivity analysis showed the potential effect of theoretical changes for both the high school and elementary school. The analysis determined that a change in the high school boundary—shifting students who would otherwise attend Skyline High School to the new high school—could alter travel patterns through several intersection with the largest impact at the 228th Avenue SE / Issaquah-Pine Lake Road SE / SE 30th Street intersection during the morning peak hour. However, the analysis showed that even if 100% of the students who now live east of that intersection were shifted to the new high school, it would not result a significant impact to that intersection or require additional mitigation. 

The sensitivity analysis showed that the planned improvements along the school’s 228th Avenue NE frontage would accommodate the full build student enrollment no matter what the school enrollment boundaries are in the future. 

3.  What traffic mitigation conditions are required for full build-out of the project? 

All required traffic mitigation measures were documented in the Final Revised SEPA Mitigation Determination of Non-Significance (MDNS) for the New Issaquah High School #4 and Elementary School #17 (January 17, 2022). This was Attachment 74 to the City of Issaquah’s staff report for the project (Link to MDNS on City of Issaquah website). The following are the transportation mitigation requirements (reference numbers from the MDNS included): 

65.     The project will pay transportation impact fees to the City of Issaquah in accordance with IMC 3.71. The District will provide school bus transportation for both elementary school students and high school students attending the proposed schools. The project would provide approximately 1,700 feet for elementary school queuing (enough space for 85 to 110 vehicles) and about 1,510 feet of available queuing space for the high school (75 to 110 vehicles), all to reduce the potential of backups onto 228th Avenue SE. The project would also provide bike racks to accommodate 68 bicycles on the site. 

66.     Construct roadway improvements on 228th Avenue SE along the site frontage, with a length of approximately 1,700 feet. Improvements would include widening the current two-lane section (one travel lane in each direction) to a four-lane section (two travel lanes in each direction), consistent with the City of Sammamish’s ultimate plans for the street. Additional turn lanes would be constructed at the site driveway intersection as needed to ensure that it would meet the City’s traffic operational standards during all times of day. 

67.     Construct a 6-foot sidewalk and landscaping along site frontage.

68.     Construction of a 6-foot sidewalk and landscaping along the east side of 228th Avenue SE from the project entrance north to SE 40th Street. 

69.     Signalize site driveway intersection at 228th Avenue SE. The intersection improvements will include ADA ramps with crosswalks and pedestrian signals. 

70.     Capacity improvements at SE 40th Street / 228th Avenue SE to be either of the following options: 

70.1. New median and striping to create a Flying T configuration and construction of a 6-foot sidewalk and landscaping along the east side of 228th Avenue SE from the project entrance north to SE 40th Street or 

70.2. New Signal and intersection improvements at the SE 40th Street/ 228th Avenue SE intersection

71.     The District shall construct roadway improvements on SE 43rd Way to extend a four-lane road section from its existing location north of the Providence Point Drive SE intersection to the project frontage. 

72.     The District shall extend a 6- foot sidewalk from the project frontage south along the west side of SE 43rd Way to connect to the existing sidewalk north of the Providence Point Drive SE intersection 

73.     The District shall post a school-zone speed limit sign on 228th Avenue SE in the vicinity of the project site. 

74.     Develop a construction management transportation plan that addresses traffic and pedestrian control during school construction. 

75.     Develop a transportation management plan to educate families about transportation options as well as the access and load/ unload procedures for the site layout. 

76.     Develop a school-event management plan for evening events with more than 1,000 expected attendees to mitigate parking impacts and ensure coordination between the schools. 

77.     ISD will discourage vehicle idling during student drop-off and pick-up times. Waiting vehicles will be monitored by a staff member, and signs shall be installed that state “no idling.”

4.  What transportation improvements are proposed for the Phase 1A portion of the proposed school project? 

All of the measures from the MDNS would be implemented for Phase 1A. The only exception is that the quantity of vehicle and bicycle parking will be reduced to reflect the smaller school associated with the phase, and no facilities will be constructed for the elementary school in this phase. The event management plan will also be tailored for the smaller school and parking supply. 

The District’s completion of the frontage improvements along 228th Avenue SW as a part of Phase 1A fulfill the City of Sammamish’s planning for that portion of the street and provides for overall project efficiencies.  

5.  What is the project doing with stormwater, including any differences for specific areas, and how will it impact the downstream tributaries and salmon population.

The school project is designed to improve stormwater management compared to existing conditions, with the goal of protecting downstream tributaries and supporting salmon habitat. Stormwater management for the project was evaluated at a site-wide level as part of the SEPA review process, rather than by individual features such as the football field.

The existing site includes access roads, parking lots, and building pads that discharge stormwater to the downstream system. Reflecting the historic construction of the previous improvements on the site prior to modern stormwater requirements, there is no treatment or flow control currently.  The project is designed to improve this existing condition by limiting runoff rates to the forested condition and treating stormwater to an enhanced level.  The water leaving the site will meet the strictest stormwater requirements of any development in the basin since stormwater codes and requirements have continued to evolve of the past 40-years. 

These measures are monitored and enforced in accordance with permit requirements, and key elements include:

Modern stormwater treatment and flow control: Runoff from roofs, pavement, and landscaped areas will be captured, treated, and released at controlled rates that reduce erosion and protect stream channels downstream.

• Water quality improvements: Stormwater facilities are designed to remove sediment and pollutants before water leaves the site, improving the quality of water entering downstream tributaries.
   
• Construction-phase protections: During construction, required erosion and sediment control measures will be in place to prevent soil and debris from entering the drainage system.
   
• Regulatory review and compliance: The stormwater system has been designed to meet or exceed current City of Issaquah and State of Washington requirements, which specifically address protection of aquatic resources, including salmon-bearing waters. The improvements to 228th are designed to meet the City of Sammamish stormwater requirements.

The stormwater design and mitigation measures are documented in the Final Revised SEPA Mitigated Determination of Nonsignificance (MDNS) issued January 17, 2022.

• Enhanced treatment and mitigation measures: the district incorporated enhanced stormwater treatment beyond minimum requirements. These measures include detention, filtration, controlled release and treatment of runoff from all pollution-generating impervious surfaces to reduce impacts to downstream waterways.
   
• Multi-agency and third-party review: Stormwater analysis and design were supported by third-party consultants and reviewed through the SEPA process and city permitting. Multiple agencies were provided opportunities to review and comment, and the City of Issaquah conducted detailed stormwater review as part of project approval.

Overall, the completed project will replace older, less-controlled drainage conditions with a comprehensive stormwater system that reduces peak flows, improves water quality, and provides better long-term protection for downstream tributaries and salmon habitat.

The system is designed to perform at or above modern standards, providing more controlled flow and improved treatment and filtering of pollutants compared to many legacy systems existing currently in the surrounding developed parcels constructed under older regulations.

6.  Why can’t the initial phase (Phase 1A) be constructed without removing all the trees?

Although building construction is phased, the site earthwork, stormwater systems, utilities and access must be constructed as a single, coordinated operation, which requires tree removal across the site early in the project.

Key reasons include:

• Earthwork volumes must be balanced across the entire site:
  The project involves large volumes of cut and fill that are designed to minimize soil export on site. Soil excavated in one area is reused elsewhere to build pads, roads, and stormwater facilities. If tree removal were limited to Phase 1A, this balance could not be achieved, resulting in significantly more truck hauling, longer construction duration, and greater overall environmental impacts.
   
• Stormwater infrastructure depends on complete on-site grading:
  Stormwater facilities, conveyance routes, and overflow paths rely on finished grades that extend beyond the Phase 1A footprint. These systems cannot be installed or function correctly without clearing and grading the site as designed. This coordinated approach is necessary to implement the full stormwater system evaluated through the SEPA process and ensure proper drainage, treatment and flow control across the site.
   
• Environmental protection during construction:
  Performing earthwork in a single, coordinated phase allows erosion control measures to be installed comprehensively and maintained effectively. Phased clearing would require repeated disturbance and re mobilization, increasing the risk of sediment reaching downstream waters.
   
• Safety, constructability, and efficiency:
  Partial clearing would require temporary slopes, stockpiling, and rehandling of soil, which increases safety risks and construction impacts compared to a single, planned earthwork operation.  If the earthwork was phased, future work including tree clearing and mass grading on an occupied school campus would also create safety risks for students.

While tree removal occurs early, it supports shorter construction duration, fewer truck trips, reduced disturbance and environmental impacts overall, and better stormwater performance. The project also includes landscape restoration and replanting once construction is complete to establish a stable, functional, and environmentally compliant campus.

7.  Was the environmental review independently evaluated or reviewed by outside experts?

Yes. While the district served as the lead agency for SEPA review, the environmental analysis and documentation were prepared with support from third-party consultants. In addition, an independent SEPA Responsible Official reviewed and issued the Final Revised SEPA Mitigated Determination of Nonsignificance (MDNS).

The process also included opportunities for review and input from multiple agencies, including local, county, tribal and state entities, as well as opportunities for public comment. The City of Issaquah reviewed project materials and conducted detailed analysis as part of permitting. This multi-layered review process helps ensure environmental considerations are evaluated thoroughly and transparently.