Climate Change Impacts to Temporary Construction Program Delivery
Climate extremes of weather (snow, floods, rain & drought) are negatively affecting project delivery schedules and budgets. Project Storm Water Pollution Prevention Plans (SWPPP) are theoretically designed for a level of Best Management Practices (BMPs) performance against a defined rain event (typically a 2 yr return frequency) in 24 hours that follows a normalized NRCS SCS rain fall distribution. This assumed normalized condition no longer applies as the storm event daily totals have changed in increased intensity, duration and frequency. One of my favorite saying’s includes rain will not stop when performing a critical operation over a sensitive water, but will stop raining once it is necessary to establish a perennial vegetative cover to terminate permit coverage. Our designs must therefore change to reflect data trends of tomorrow if our goal is defined by definitions of reasonable expenditures of time and money with a defined service life of the implemented project. Even if temporary impacts of climate impacts are ignored, projects that are designed to last 50 years will be rebuilt multiple times just to reach 50 years. But temporary impacts must not be ignored. The cost of incorporating climate resilient designs into today’s budget is cheap (mobilization, energy, labor, materials will never be lower cost than today) in comparison to performing the task again. Estimating SWPPP BMPs that work once and well for the intended service life is critical for controlling true costs and protecting water resources. This presentation will describe potential SWPPP and project adjustments that incorporate climate change data trends (from NOAA Atlas 14) for weather impact resilience during construction operations. Examples include inlet protection upgraded to lift-station pump bypass to sediment traps or other treatment systems; Perimeter land controls upgraded to silt fence fabric attached to J-Barriers; Sheet pile isolation barriers to replace silt curtain when working in waters; Vehicle exit controls will actually have to perform to prevent sediment from being tracked onto paved surfaces; work surfaces that prevent erosion from occurring. Part of the answer will explore going back in time to the hand wheel borrow and temporary trestle bridges, and subsequent lower disturbance levels. Has hydraulic and machine control in the pursuit of greater efficiencies increased delays due to weather extremes? Are there lessons from our grandparent’s construction methods that are applicable today? The class will be introduced to modernized construction practices of the past as it applies to working in, over, and adjacent to climate impacted waters of the states.