Committee Report - Flood - 4-11-22 — File 213480

Flood Forum Special Committee Page 1 of 3 Printed 4/12/2022 April 11, 2022 REPORT OF THE FLOOD FORUM SPECIAL COMMITTEE Attendee Name Title Status Arrived Jefferson Thomas ("J.T.") Scott Chair Present Willie BurnleyJr. Vice Chair Present Kristen Strezo City Councilor at Large Present Others present: Brian Postelwaite-Engineering, Rich Raiche-IAM, Lucica Hiller- Engineering, and members from the Gilman Square Neighborhood Association Matthew Carlino-resident, Christine Carlino-resident and Steven Nutter-resident The meeting was held virtually and was called to order at 6:04 p.m. by Chairperson Scott and adjourned at 7:02 p.m. Approval of the December 2, 2020 Minutes RESULT: ACCEPTED 213112: That the Director of Engineering and the Director of Infrastructure and Asset Management consider implementing a pilot program for Green Infrastructure as a means to reduce issues of flooding in the Gilman Square Neighborhood. The chair sponsored several members from the public to present slides. Matthew Carlino, Christine Carlino and Steven Nutter presented slides for Gilman Square Stormwater and Green Infrastructure Solutions. The members of the Gilman Square Neighborhood Association are Matthew Carlino as civil engineer, Christine Carlino an architect, and Steven Nutter an urban planner. They presented an overview of what they have been seeing in the neighborhood in terms of flooding and possible solutions. Matt’s background is in stormwater designs. He also has expertise involved in contamination and remediation. Christine has experience in the greater Boston area for 15 years. She is now working on the other end with her main focus in master planning for MIT Laboratory with experience in capital projects and planning. Steven’s focus is on transportation and landscape planning. He was previously on the board of Livable Streets and now runs an organization called Green Cambridge teaching children how to grow foods. Pictures were shared of Gilman Square flooding on Bradley, Medford and Richdale Streets. These issues have been happening for a while. Mr. Carlino stated the City of Somerville has one of the oldest sewer lines. Sewage backflows into homes caused by pressure build up. Gilman

Flood Forum Special Committee Page 2 of 3 Printed 4/12/2022 Square has flooded consistently for many years. Separate storm and sewer lines are not budgeted for Medford Street and not planned in the 10-year CIP. Mr. Carlino talked about building a large-scale storage tank. Tanks needs to be maintained and sanitized which will require a maintenance crew. The alternative to the tank is green infrastructure and can have a tree trench. The water can come off the street and go into a basin which can be stored underneath the trees. Mr. Carlino talked about stormwater bump-outs and how it could benefit the City of Somerville. He states it is considerably cheaper than tanks or sewer stormwater separation. Stormwater bump-outs can increase pedestrian safety at intersections, calm traffic and daylights corners for safer traffic merging. Ms. Carlino stated the case study intersection between Broadway and Highland could store 40% of the estimated tank that could go into the Homan’s site. The stormwater bump-out would be under $1M. Matt suggested to look at the city of Philadelphia to see what they are doing. The members from the Gilman Square Neighborhood Association are recommending a pilot on Medford and School street. They do not want to see the tank on the Homan’s site nor do they want to wait 20 years before anything is done. They also recommend having a consultant to guide the city through this process. Other cities have developed green streets program and implement a public works team to handle the maintenance. He also suggested community involvement such as Green Stewards program to educate kids. Green infrastructure has been successfully implemented in Portland, OR, Grand Rapids, MI Arlington and Cambridge, MA. This makes financial sense to do this program. Mr. Nutter stated that City of Somerville is 87% asphalt. Councilor Strezo asked about the cost of the program and would like a detailed financial plan. She also asked about accessibility and asked if the city would lose any parking. Ms. Carlino stated no parking would be lost with the stormwater bump-outs. Mr. Carlino stated they got their numbers from Mystic River project from Arlington area with each bump-out cost $6,000 each. Director Raiche shared slides on Green Stormwater Infrastructure Feasibility study and other areas. In 2018/19 the feasibility study was completed which was awarded to Somerville by DEP and MEMA. The study looked at about 10 different areas in the city. The reports were posted on SomerVoice website. He also stated the floods vary by neighborhood and by size of storms. The city is committed to implementation of GSI. They looked at potential setbacks and where they can put stormwater in a full range. The next steps are to make an intervention for regulatory planning by 2023-2024. See slides for citywide GSI potential locations. The implementation in the right of way is very limited. There is a large volume of water to be controlled. Councilor Burnley asked questions for city staff of what criteria is used when sidewalks are uprooted. Also questions about the removal of the tank. Director Raiche stated they would continue the public process and would have the Gilman Square association and other to work with the city to look at the costs. Mr. Raiche stated that a pilot would probably not hit the ground until 2024. The chair talked about next steps of the timeline and the willingness from engineering and IAM team to work on the numbers.

Flood Forum Special Committee Page 3 of 3 Printed 4/12/2022 RESULT: KEPT IN COMMITTEE Reference Material: • CC Flood Committee IAM 2022Apr11 (with 213112) • Gilman Square Green Infrastructure_041122 (with 213112)