CPESC exam Questions With Complete Solutions

What are the 5 factors that influence erosion? correct answer: Soil erodibility, topography, vegetative cover, season, climate (rainfall) What influences soil erodibility? correct answer: Soil texture, structure and % of OM How does vegetative cover influence erodibility? correct answer: Top growth reduces raindrop impact, filters sediment and slows down runoff velocity; roots hold mass particles together How can you decrease erodibility in relation to topography? correct answer: Increase slope roughness What climate characteristics affect erodibility? correct answer: Rainfall intensity, duration and frequency Why does frequent rainfall increase erodibility? correct answer: The soil becomes saturated and no more water can infiltrate which increases runoff volume Why is erosion potential high in the spring if it rains? correct answer: Water can't infiltrate the frozen subsoil which increases runoff volume What are some ways urban development impacts erosion hazards? correct answer: Changes hydrology (GW flow, drainage), disturbs large amounts of soil, removes plant cover BMP considerations for clearing and grubbing? correct answer: Preserve existing vegetation; clear only what is required for immediate construction activity BMP considerations for mass grading? correct answer: Create principle basins, traps, barriers, diversions and channels; temporary stabilization; manage concentrated runon and runoff