8.3 Floodplains 2025 Update 20250504 — File 25-0907

Somerville Zoning Ordinance Date Printed: 7/12/2023 1 8.3 FLOODPLAINS (FP) Contents: 8.3.1 Intent 8.3.2 Purpose 8.3.3 Applicability 8.3.4 District Boundaries 8.3.5 Definitions 8.3.6 Compliance with Other Regulations 8.3.7 Development Limitations 8.3.8 Notification of Watercourse Alteration 8.3.1 Intent a. To ensure public safety through reducing the threats to life and personal injury. b. To eliminate new hazards to emergency response officials. c. To prevent the occurrence of public emergencies resulting from water quality contamination and pollution due to flooding. d. To avoid the loss of utility services which if damaged by flooding would disrupt or shut down the utility network and impact regions of the community beyond the site of flooding. e. To eliminate costs associated with the response and cleanup of flooding conditions. f. To reduce damage to public and private property resulting from flooding. 8.3.2 Purpose a. To require development to be in compliance with applicable provisions of the Massachusetts State Building Code and Massachusetts General Laws. b. To appropriately limit development within floodways to reduce obstructions to flood flows and reduce flooding impacts on the community. 8.3.3 Applicability a. Where the provisions of this Section conflict with those found elsewhere in this Ordinance, the provisions of this Section apply. 8.3.4 District Boundaries a. The FP overlay district includes all special flood hazard areas within the City of Somerville designated as Zone A or Zone AE on the Flood Insurance Rate Map (FIRM) issued by the Federal Emergency Management Agency (FEMA) for the administration of the National Flood Insurance Program. b. The map panels of the Middlesex County FIRM, dated June 4, 2010, that are wholly or partially within the City of Somerville are: i. 25017C0417E ii. 25017C0419E iii. 25017C0436E iv. 25017C0438E

Somerville Zoning Ordinance Date Printed: 7/12/2023 2 v. 25017C0439E vi. 25017C0576E vii. 25017C0577E i. The map panels of the Middlesex County FIRM, in effect as of July 8, 2025, that are wholly or partially within the City of Somerville are: a) 25017C0417F b) 25017C0419F c) 25017C0436F d) 25017C0438F e) 25017C0439F ii. The map panels of the Middlesex County FIRM, dated June 4, 2010, that are wholly or partially within the City of Somerville and in effect are: a) 25017C0417F b) 25017C0419F c.b. The boundaries of the FP overlay district are defined by the 100-year base flood elevations shown on the FIRM and further defined by the Middlesex County Flood Insurance Study (FIS) report dated June 4, 2010July 8, 2025. d.c. The FIRM and FIS report are incorporated herein by reference and are on file with the City Clerk, Planning Board, Building Official, Conservation Commission and City Engineer. 8.3.5 Definitions a. For the purpose of this overlay district alone, the definitions of 44 CFR 59.1 apply. 8.3.6 Compliance with Other Regulations a. All development within the FP overlay district must be in compliance with, or operating under duly approved Hardship Variances from, the following regulations: i. Sections of the Massachusetts State Building Code which addresses floodplain and coastal high hazard areas (currently 780 CMR 120.G, “Flood Resistant Construction and Construction in Coastal Dunes”) ii. Wetlands Protection Regulations, Department of Environmental Protection (DEP) (currently 310 CMR 10.00) iii. Sections of Massachusetts General Law which address altering of land bordering waters (currently Chapter 131, Section 40 of the Massachusetts General Laws) iv. Inland Wetlands Restriction (currently 310 CMR 13.00); v. Minimum Requirements for the Subsurface Disposal of Sanitary Sewage (currently 310 CMR 15, Title 5) 8.3.7 Development Limitations a. In “A” Zones, the Building Official shall use the best available Federal, State, local or other floodway data to prohibit encroachments in floodways which would result in any increase in flood levels within the overlay district during the occurrence of the base flood discharge. b. In Zones AE: i. along watercourses that have regulatory floodways designated within the City of Somerville on the FIRM, encroachments are prohibited in the regulatory floodway which would result in any increase in flood levels within the community during the occurrence of the base flood discharge.

Somerville Zoning Ordinance Date Printed: 7/12/2023 3 ii. along watercourses that have not had a regulatory floodway designated, no new construction, substantial improvement, or other development is permitted unless it is demonstrated that the cumulative effect of the proposed development, when combined with all other existing and anticipated development, will not increase the water surface elevation of the base flood discharge. c. The following uses of low flood damage potential and causing no obstructions to flood flows are encouraged provided they are permitted in the underlying district and they do not require structures, fill, or storage of materials or equipment: i. outdoor recreational uses ii. conservation of water, plants, wildlife iii. buildings lawfully existing prior to the adoption of these provisions 8.3.8 Notification of Watercourse Alteration a. The Building Official shall notify the following of any alteration or relocation of a watercourse: i. Adjacent Municipalities ii. The State Coordinator for the National Flood Insurance Program at the Massachusetts Department of Conservation and Recreation iii. Program Specialist for the National Flood Insurance Program at the Federal Emergency Management Agency, Region 1 Office.