engleski

Problems With Sedimentation in Wetland BMP During Highway Construction and Use

This paper analyses the economical and ecological problems associated with surface soil erosion on construction sites, as well as, resulting transport of sediment and its deposition in water bodies – natural streams, reservoirs, wetlands, lagoons, etc. Investigation was focused on the influence of water forces, which involves the action of raindrops and surface runoff. Impacts of highway construction and use in Istra region (Croatia) on nearby lagoon BMP are analyzed in this paper. Special interest on selected area is given from the aspect of hilly terrain configuration and flysch geological characteristics, which altogether result with increased erosion potential. The selected segment of highway is characterized by implementation of two runoff treatment structures – separator (grit and grease chamber) and treatment lagoon The purpose of the study was to mathematically express the soil loss on selected area due to generation of erosion processes and further transport of sediments. Altogether, several investigations were carried out concerning the erosion BMPs implementation. One presumes no protection while others include the use of erosion control measures (BMPs) on disturbed area. The segment area with cut slopes only has been analyzed. RUSLE (Revised Universal Soil Loss Equation) method was used to calculate the sediment quantities generated on observed watershed. Calculated values were encountered in numerical model USEPA SWMM-5 to simulate the overall sediment transport and its accumulation in the lagoon. Lagoon treatment efficiency was calculated for each scenario that was analyzed. Simulation results were used as input parameters in estimation of additional expenses caused by frequent and costly maintenance. These expenses were subsequently compared with direct expenses of erosion and sediment protection measures at construction site. More detailed economical analysis was conducted due to the unpredictable behavior of some parameters included in RUSLE equation. The uncertainty analysis was performed by using the Monte Carlo simulation.

Runoff; Rainfall; Stochastic hydrology; Hydrology

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