Floodplain Management (Exam 4) Questions and Answers 100% Solved

Floodplain Management (Exam 4) Questions and Answers 100% Solved Floodplain any land area susceptible to being inundated by floodwaters from any source Floodplain management A decision making process that aims to achieve wise use of the nation's floodplain (FEMA) 11 How many named systems strike the Atlantic basin a year (on average)? coastal/tidal what type of flooding occurs due to hurricanes or other major storms? Riverine/backwater Flooding caused by exceptional rainfalls, spring thawing, and inability of stream channel to accommodate runoff from its watershed fertile Floodplains normally have ___ soils surface runoff urban development has increased ___ ___ which increases potential hazards in a floodplain 100 year flood flood that has a 1% chance of being equaled or exceeded in any given year 500 year flood flood that has a 0.2% chance of being equaled or exceeded in any given year coastal flooding flooding minimized using mostly nonstructural techniques, but some structural riverine flooding flooding minimized using both structural and non structural techniques benefits of floodplains -modulation of floods - productive soils - maintenance of water quality - groundwater recharge - diverse biotic communities - cultural, scientific, and recreational value rational method Q=CIA method for estimating peak runofff rates in small areas (Q-peak rate, C- Coefficient of runoff based on tyoe of surface, I-rain intensity, A- drainage area) hyetograph plot of precipitation over time, derived from accurate filed measurements of precip. intensity at intervals (Bar graph appearance) hydrograph plots discharge over time at a given point in a channel, inflow and outflow (line graph = runoff(y) and time(x)) surface, subsurface, runoff what are the three elements that make up hydrographs groundwater runoff water that maintains a streams base flow during periods of arid weather three assumptions of a hydrograph constant baseline, proportional ordinate (diff. intensities are proportional), superposition Frequency Analysis procedure for estimating the frequency or probability of recurrence of past and future events homogeneous data must be ____ and independent probability the ratio of favorable events to the total events Complete duration series sample data type where all the data points taken during elapsed time frame annual series sample data type with one value per year, such as max peak flow each year partial duration series sample data type where all values above a certain base extreme value series sample data where the largest or smallest observation in a given time interval