Hoffman’s Mill Dam Removal

The Brandywine Conservancy and Museum of Art is requesting bids for the complete demolition and removal of Hoffman's Mill Dam, a run-of-river rockfill dam across the Brandywine Creek in Chadds Ford, Pennsylvania, with bids due July 20, 2026 at 5:00 PM via PennBid. Attendance at a mandatory pre-bid conference on July 7, 2026 at 10:00 AM is required for bid eligibility; bids will not be accepted from contractors who do not attend.

The scope includes selective demolition, dewatering and water control of the existing impoundment, erosion and sediment control in accordance with Pennsylvania Department of Environmental Protection guidelines, riprap placement using relocated dam stone, bank stabilization, site restoration of paved surfaces and fencing, topsoil application (minimum 4 inches), and seeding. The contractor must maintain constant downstream flow in the Brandywine Creek (estimated median flow of 320 cubic feet per second) throughout the work, protect the historic mill race, wetlands, and rare plant species (Rotala ramosior), and comply with habitat-protection windows: instream work limited to April 15 through October 15 for northern red-bellied cooter protection, and tree removal forbidden between May 15 and July 31 for bat protection. A 20-inch diameter high-pressure gas pipeline operated by Columbia Gas Transmission Corporation requires minimum 7-foot to 10-foot offsets and equipment matting. Riprap material must come from a single PennDOT-approved quarry with minimum bulk specific gravity of 2.5 and maximum absorption of 2%. Mobilization costs cannot exceed 4% of total bid price.

Bids must be lump-sum with 10% bid security. Substantial completion is due by October 15, 2026, and final completion by December 31, 2026. Liquidated damages are $2,000 per day for delays beyond substantial completion. Performance, payment, and maintenance bonds (100%, 100%, and 10% of contract price, respectively) are required. Required insurance includes workers' compensation, commercial general liability ($1,000,000 per occurrence / $2,000,000 aggregate), automobile liability, umbrella liability ($5,000,000), and contractors' pollution liability ($1,000,000 per occurrence / $4,000,000 aggregate). Progress payments are monthly with 10% retainage. The owner is exempt from Pennsylvania sales and use taxes; bids must not include taxes. Bidders must provide financial data, previous experience, state contractor license information if applicable, and subcontractor and supplier details within five days of bid opening or upon request.