Remediation Timeline Calculator

Environmental cleanups rarely fail on the engineering — they run long because of the bureaucratic and biological phases surrounding it, and this calculator lays out all seven so a rough total is visible from the start. It sums independent duration estimates for investigation (skipped entirely if the Phase II ESA is already done), remedial investigation/feasibility study, design and permitting, construction, active operation, closure monitoring, and regulatory closeout, each scaled by site size, contaminant complexity (1-5), regulatory burden (1-5), and community involvement (1-5). The operation phase is where technology choice dominates: the calculator applies a per-technology base duration and per-acre scaling factor, so pump-and-treat (24-month base, 6 months per acre) and monitored natural attenuation (36-month base, 12 months per acre) run far longer than excavation (2-month base) or in-situ chemical injection (3-month base), reflecting that excavation physically removes the source while MNA simply waits for natural biodegradation to run its course.

Closure monitoring scales with regulatory burden alone, capturing the reality that a state voluntary cleanup program moves faster than a federal Superfund NPL site regardless of the remedy chosen, while regulatory closeout scales with both regulatory burden and community involvement, since sites with an active community advisory group typically carry extra public-notice and comment steps before a No Further Action letter can be issued. The "longest phase" output flags the practical critical path, which is usually operation or closure monitoring rather than anything upfront. Treat every number as a planning-level estimate built from typical EPA Superfund and state brownfield program durations, not a contractual schedule — actual timelines can swing widely with agency responsiveness, unexpected contamination discovered mid-project, or litigation, none of which this model can anticipate.