Upper Van Horn Reservoir Dam Improvement Project - Design and Permitting

Challenge

The Upper Van Horn Reservoir Dam is a Significant Hazard potential, Intermediate-sized embankment dam owned and operated by the City of Springfield through their Department of Parks, Buildings, & Recreation Management. The dam is the roadway embankment for Armory Street, roughly between Chapin Terrace to the southeast and Beauchamp Street to the northwest. Immediately downstream of the Upper Van Horn Reservoir Dam is the Lower Van Horn Reservoir. The two reservoirs are located along an unnamed tributary stream to the Connecticut River. The upper dam and its impoundment are located within the City’s right-of-way for Armory Street and within Van Horn Park.

The dam is comprised of an earthen embankment with twin 8 ft wide x 5 ft high box culverts serving as the primary, uncontrolled spillway. These culverts discharge to a steeply sloped concrete spillway chute which flows into the downstream Lower Van Horn Reservoir, which in turn outlets to a 48-inch diameter concrete pipe, which is part of the City of Springfield’s stormwater drainage system, and which ultimately discharges into the Connecticut River, approximately 1.5 miles west of the Upper Van Horn Reservoir Dam.

The dam is currently rated in Poor Condition, with deficiencies, including:

• Trees and woody vegetation along the upstream and downstream slopes
• Significant erosion on the upstream and downstream slopes
• Uncontrolled clear seepage along the toe of the dam
• Concrete condition issues
• Uncontrolled discharge from a ponded area near the left downstream groin/abutment contributing to erosion
• Animal burrows
• Insufficient section relative to seepage and stability
• Lack of a low-level outlet or provisions for lowering the water level
• No Emergency Action Plan
• No Operations and Maintenance Plan

Solution

GZA helped the City prepare a successful Dam and Seawall Grant Application to cover design and permitting services related to improvements needed to bring the Upper Van Horn Reservoir Dam into Good Condition.

GZA is currently working on continued design development and is pursuing project permits, which will include the following:

• Massachusetts Environmental Policy Act (MEPA) Environmental Impact Report (EIR)
• Section 404 Authorization (Army Corps of Engineers)
• Section 401 Water Quality Certificate (MassDEP)
• Chapter 253 Dam Safety Permit (MA Dept. of Conservation and Recreation Office of Dam Safety)
• Order of Conditions (OOC)/Wetlands Notice of Intent
• EPA Construction General Permit (CGP) Notice of Intent

Benefit

The proposed design will include:

• Removal of all trees and woody vegetation and establishment of turf along embankment portions of the dam
• Flattening of the overly steep slopes and installation of stability berm
• Filling of all areas of erosion and burrows Installation of a toe drain and filter on the downstream slope
• Concrete repairs to the existing box culverts and construction of a new spillway chute
• Grouting and partial removal of a former outlet line from the pond
• Installation of a permanent new access for maintenance
• Construction of a new drainage system along the streetline with new outlets into the spillway chute
• Re-culverting an area of stream along the downstream slope where the former culvert piping has failed
• Installation of a siphon for drawdown capabilities