Stormwater Pollution Prevention and Erosion Control, Exams of Construction

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Erosion - correct answer,,,,process in which, by the actions of wind and/or water, soil particles detached and transported Sediment - correct answer,,,,eroded material suspended in wind or water Sedimentation - correct answer,,,,deposition of eroded material Types of Erosion - correct answer,,,,splash sheet rill gully channel Splash erosion - correct answer,,,,raindrop impact energy is enough to dislodge surface sediments sheet erosion - correct answer,,,,caused by rain splash detaching soil particles lifting them up and removing them by shallow "sheets" of water flowing down the sloped soil surface Rill Erosion - correct answer,,,,as flow concentrates, small channels begin to form in the soil surface Gully Erosion - correct answer,,,,Formed when runoff cuts rills deeper and wider or when flows from several rills come together and form a large channels Channel Erosion - correct answer,,,,may become unstable due to increased flows or changes in upstream sediment load

Natural erosion - correct answer,,,,generally considered due to the influences of climate on the surface of the earth Accelerated erosion - correct answer,,,,natural erosion plus human activities What problems can accelerated erosion cause? - correct answer,,,,Unrestricted development removal of surface cover increased imperviousness poor stewardship Problems associated with construction related erosion - correct answer,,,,problems for down slope property owners nuisance problems on streets clog streams and storm drains increased turbidity downstream cover sensitive habitat with sediment Identify instream damages of sediment - correct answer,,,,destruction of spawning areas, food sources, habitat direct toxicity to wildlife lake degradation filling of navigation channels impacts to commercial fisheries reduction of water storage capacities Suspended material - correct answer,,,,sediment can affect light penetration, channel stability, fisheries and habitat Name Off stream damages - correct answer,,,,Increased flood hazards increased water treatment costs

decreased capacity in conveyance facilities higher infrastructure maintenance costs What has increased the amount of impervious surface in our watersheds? - correct answer,,,,Urbanization and development priority pollutants include - correct answer,,,,nutrients pathogens heavy metals toxics sediment salts detergents hydro carbons Clean Water Act (CWA) - correct answer,,,,Federal Water Pollution Control Act enacted to restore and maintain the chemical, physical and biological integrity of the waters of the US administered by USEPA Section 401 - correct answer,,,,water quality certification requires applicant, including any construction or operation of a facility, to obtain certification to discharge ANY pollutant. administered by the State Section 402 - correct answer,,,,NPDES Regs NPDES - correct answer,,,,National Pollutant Discharge Elimination System MS4 - correct answer,,,,Municipal Separate Storm Sewers Systems

NURP - correct answer,,,,Nationwide Urban Runoff Program 1987- led to EPA regulating stormwater Phase I (1987 - 1992) - correct answer,,,,already covered by NPDES permit facilities that engage in industrial activity Large municipal storm systems (>250,000) Medium municipal storms systems (100 - 250 K) facilities that EPA said were significant contributors Storm Water Implementation Rule - correct answer,,,,enacted April 1992, identified minimum requirements for NPDES stormwater permits Section 404 - correct answer,,,,regulates dredge / fill permitting into waters of the US administered by USACE CZARA - correct answer,,,,Coastal Zone Act Reauthorization Amendments (CZARA) of 1990 requires coastal zone states to develop Coastal Nonpoint Pollution Control Programs section 6217 nonpoint source in coastal areas stormwater - correct answer,,,,stormwater runoff, snow melt runoff, and surface runoff and drainage NPDES stormwater regulation say - correct answer,,,,stormwater must be in any discernable, confined, and discrete conveyance, including but not limited to any pipe, ditch, channel, tunnel, well, discrete fissure, container, rolling stock, concentrated feeding operation.... waters of the US - correct answer,,,,waters used for interstate or foreign commerce

all interstate waters including wetlands all other waters, the use ofr degeration of which would affect interstate or foreign commerce impoundments of waters territorial sea wetlands adjacent to waters above Phase II - correct answer,,,,December 1999, require construction sites disturbing equal to or greater than 1 acre and less than 5 to control pollutants in stormwater runoff. SWMP - correct answer,,,,Stormwater Management Plan 6 minimum measures of SWMP - correct answer,,,,Public Education and Outreach Public Participation / Involvement Illicit Discharge Detection and Elimination Construction Site Runoff Control Post Construction Runoff Control Pollution Prevention / Good Housekeeping (PPICPP) Purpose of Clean Water Act - correct answer,,,,protect the beneficial uses of surface waters Water quality standards must do the following - correct answer,,,,Include provisions for restoring and maintaining the chemical, physical and biological integrity of state waters Achieve a level of water quality that provides for the protection and propogration of fish, shellfish and wildlife and recreation in an on the water Consider the use and value of state waters for public water supplies, propagation of fish and wildlife, recreation, agriculture and navigation

TMDL - correct answer,,,,Total Maximum Daily Loads define the amount of a particular pollutant that a water body can assimilate on a daily basis without violating applicable water quality standards. what does TMDL do - correct answer,,,,section 303 d of the clean water act established TMDL process to guide the application of state water quality standards. TMDL process (3 steps) - correct answer,,,,Identify Quality Limited waters (compile 303d list) Establish Priority Waters/ Watersheds for TMDL development Develop TMDLs TMDL - correct answer,,,,sum of the waste load allocations for point source, nonpoint source and natural sources plus a margin of safety. They must identify links between: water body use impairment or threat of concern, cause of impariment, load reductions or actions needed to remedy or prevent the impairment ELG - correct answer,,,,Effluent Limitation Guidelines Effective, February 2010, requires operators to sample stormwater discharges and comply with a numeric standard for turbidity. August 2011, 20 acres of more Feb 2014, sites more than 10 acres must comply with numeric effuent limitations (280 NTUS) NEL waived for events exceeding 2 year 24hr storm State regulations - correct answer,,,,EPA delegated authority or EPA administered Permittee - correct answer,,,,EPA prefers general contractor

6 phases of stormwater pollution prevention for construction activiites - correct answer,,,,Site evaluation and design development Project Assessment Control selection and plan design Certification and notification Construction / implementation Final stabilization / termination Site Evaluation (steps) - correct answer,,,,identify characteristics of the site: soils, surface waters, etc. develop a site plan design (disturb smallest area, avoid sensitive areas, etc.) describe construction activity Prepare pollution prevention site map Project Assessment - correct answer,,,,second phase in preparing SWPPP Measure site areas Determine drainage area Calculate the runoff BMP Selection and Plan Design - correct answer,,,,phase 3 review state and local requirements select erosion and sediment controls stormwater management controls other controls

prepare inspection and maintenance plan description of controls sequence of activities How quickly does EPA general permit require site to be stabilized - correct answer,,,,within 14 days after the last disturbance EPA general permit requires how many acres and how much storage for temporary sediment basin? - correct answer,,,,A temporary of permanent sediment basin be installed in any drainage location where more than 10 acres in the upstream drainage area are disturbed at one time. The basin must provide at least 3600 cubic feet of storage for every acre of land that it drains. EPA general sequencing - correct answer,,,,Install down slope and side slope perimeter controls before land disturbance occurs do not disturb an area until necessary for construction to proceed cover or stabilize disturbed area as soon as possible time construction activiites to limit impact from seasonal climate changes or weather events delay construction of infiltration measures until the end of the construction project when upstream drainage areas have been stabilized do not remove temporary perimiter controls until after all upstream areas are finally stabilized EPA general permit inspection frequency - correct answer,,,,every 7 days or within 24 hours of 0.5 inch storm event

EPA corrective action frequency - correct answer,,,,as soon as possible but in no case later than 7 days after the inspection 3 types of enforcement actions - correct answer,,,,Administrative orders Civil actions Criminal Prosecutions EPA maximum for civil penalties - correct answer,,,,37,500 per violation...no maximum limit Beneficial uses - correct answer,,,,aquatic life swimming fishing and fish consumption boating aesthetic enjoyment first regulations of stormwater - correct answer,,,,Nov 16, 1990, stormwater application rule April 1992, stormwater implementation rule what are NPDES exempt - correct answer,,,,agricultural return flows and runoff from silviculture oil and gas operations NPDES Phase 1 - correct answer,,,,5 acres of more disturbance includes clearing, grading and excavation smaller parcels part of larger plan that affects at least 5 acres Waste Load Allocations (WLA) - correct answer,,,,once TMDL determined, regulatory agency allocates a portion to each source of that pollutant within a particular watershed

Administrative Order - correct answer,,,,EPA can impose fines and penalties without court action Maximum is 11,000 per day with a maximum of 32,500 for CLass 1 offenses, 16,000 per day and max of 177,000 for class II offenses... Hazards associated with urban developments - correct answer,,,,soil exposed to erosion from wind and water increased water runoff, soil movement and sediment accumulation from: removal of plant cover, construction of impervious areas, changes in drainage areas caused by grading, changes in volume and duration of flows caused by altering steepness, distance and surface roughness, soil compaction by heavy equipment, ... Factors that influence erosion - correct answer,,,,Soil erodibility Vegetative Cover Topography Climate Season Soil Erodibility - correct answer,,,,vulnerability of a soil to different erosion processes. Soil structure, texture and percentage of organic matter influence erodibility. The presence of clay or organic matter tends to decrease soil erodibility. Clays are cohesive and tend to bind soil particles together, organic matter helps to maintain stable soil structure Vegetative Cover - correct answer,,,,top growth shields the surface from raindrop impact while the root mass holds soil particles in place. Filter strips filter sediment from runoff, grasses slow velocity and maintain infiltration What are the most important factors in minimizing erosion during development - correct answer,,,,Establishment and maintenance of vegetation Topography - correct answer,,,,Slope length and steepness influence volume and velocity of surface runoff. Long slopes deliver more runoff to the base of the slopes and steep slopes increase runoff velocity. Both enhance potential for erosion

Climate - correct answer,,,,As frequency of rainfall increases, water has less chance to drain through the soils. Soil remains saturated and runoff volume may increase. Season - correct answer,,,,seasonal variation in temperature and rainfall defines periods of high erosion potential during the year Recommenced Erosion and sediment control scales - correct answer,,,,1 in = 20 ft 1 in = 30 ft 1 in = 40 ft 1 in = 50 ft contour intervals should be 2 feet or less Steps in Construction Sequencing - correct answer,,,,Pre Construction : mark sensitive areas Construction Access: construction entrances, etc Sediment Barriers and Traps: install basin after site assessed Runoff control: diversions, outlet protection Runoff Conveyance Land Clearing and Grading Surface Stabilization Building Construction Landscaping and Final Stabilizaiton 4 steps in planning process - correct answer,,,,Design SWPP to match project Determine limits of clearing Divide site into natural drainage areas Design erosion and sediment control practices Major variables that affect soil erosion by water - correct answer,,,,susceptibility of soil to erosion

potential erosivity of rainfall and runoff soil protection by plant cover S - correct answer,,,,Slope steepness factor ratio of soil loss from the field slop gradient to soil loss from a 9% slope under otherwise identical conditions L - correct answer,,,,Slope length factor ration of soil loss from the field slope length to soil loss from a 72.6 ft length under identical conditions K - correct answer,,,,soil erodibility factor the soil - loss rate per erosion index unit for a specific soil P - correct answer,,,,Erosion Control Practice Factor ratio of soil loss with certain conservation practice to that of no practice C - correct answer,,,,Cover management factor ratio of soil loss from an area with specified cover and management to soil loss from an identical area in a bare condition USLE Universal Soil Loss Equation - correct answer,,,,quantifies six factors: rainfall and runoff erosiveness, soil erodibility, slope length, slope steepness, cover management practices and support conservation practices What is the major soil conversation planning tool - correct answer,,,,USLE

Sediment yield - correct answer,,,,the amount of eroded soil that is delivered to a point in the watershed that is remote from the original of the detached soil particles RUSLE - correct answer,,,,A = R x K x LS x C x P erosion model designed to predict the longtime average annual soil loss (A) carried by runoff from specific slope s in specified management conditions A - correct answer,,,,computed spacial average soil loss and temporal average soil loss per unit of acres expressed in the units selected for K and for the period selected for R. Typically selected in tons per acre per year R - correct answer,,,,Rainfall-runoff erosivity factor Rainfall erosion index plus a factor for any significant runoff from snowmelt What does RUSLE not apply to? - correct answer,,,,Don't use RUSLE for disturbed forested conditions RUSLE - correct answer,,,,users need to be aware that A (in addition to being longtime average annual soil loss) is the AVERAGE loss over a slope and that the losses at various parts of the slope may differ greatly from one another. On a long uniform slope, where is the most loss? - correct answer,,,,the loss from the top is lower than the slope average and the loss from the bottom is considerably higher isoerodent map - correct answer,,,,tool for rainfall erosion factor (r) soil erodibility - correct answer,,,,ease with which soil is detached by splash during rainfall or by surface flow or both... (K) Soil Layers - correct answer,,,,Surface Soil (A layer): upper part of natural horizon (topsoil) generally dark in color and 0-10 inches thick

Subsoil (B layer): subsoil between A layer and parent material, 10-26 inches thick Substratum (C layer) upper part of parent material, 26-60 inches thick Slope Length (L) - correct answer,,,,effect of topography on erosion is LS erosion increases as slope length increases, which is represented by L surface runoff will usually concentrate in less than 400 feet, which is a practical slope length limit slope length and steepness affect sheet and rill erosion Slope Steepness (S) - correct answer,,,,the influence of slope gradient on erosion. Estimated in field by use of a clinometer, abney level or other device. May be estimated from contour maps having 2 ft contour intervals if care used. Soil loss increases more with steepness than with length Topographic factor (LS) - correct answer,,,,combined LS factor in the RUSLE represents ratio of soil loss on a given slope length and steepness to a soil loss from a slope that has a length of 72.6 ft and a steepness of 9% total estimated erosion - correct answer,,,,sum of the calculated sheet and rill erosion plus other erosion wind erosion - correct answer,,,,areas that are not adequately protected when high velocity winds blow across the land. field conditions best described as bare, loose and dry, soil movement begins when wind reaches 13 miles per hour at one foot above ground surface

suspension - correct answer,,,,very fine particles (<0.05mm) soil particles and aggregates that are carried high into the air saltation - correct answer,,,,movement of the intermediate size (,0.05 to 0.5mm) particules (very fine, fine and medium sand) that are lifted a short distance into the air and fall back to dislodge more soil. This accounts for one half of total soil movement surface creep - correct answer,,,,movement of large sand particles (0.5mm and larger) along the ground surface. The saltation process dislodges these particles and the wind rolls them. practices used to make soil surface condition less erodible by the wind include - correct answer,,,,ridging (to trap soil particles and decrease surface area exposed to wind velocity) turning over the soil to increase cloddiness irrigating to increase cohesiveness and weight of soil particles and decreasing detachability growing vegetation to increase organic matter and increase aggregation in the surface area using vegetation as surface cover why are wind erosion guides used - correct answer,,,,to determine potential soil loss from wind and the methods used to reduce this loss MUSLE - correct answer,,,,T=95(V x Qp)0.56 x l x LS xC x P T= sediment yield in tons for a storm event V = volume of runoff for the storm event, acre- feet Qp= peak flow for the storm event, cfs K, LS, C, P = same in RUSLE

Other erosion - correct answer,,,,soil loss from gullies, channels and other concentrated flow may be determined by calculating the annual volume of soil removed from the eroded areas. Annual tons of soil loss can be determined by multiply the volume by the weight of the soil Partial year soil loss - correct answer,,,,a value obtained with RUSLE may be modified by a factor M to estimate the soil loss for a portion of the year Hydrologic Cycle - correct answer,,,,Precipitation - Surface Runoff - Infiltration - Transipiration- Percolation -Evaporation Runoff Volume - correct answer,,,,Q = volume of the runoff in watershed inches multiplied by the watershed area. Factors affecting runoff - correct answer,,,,precipitation (P) time watershed area ground cover antecedent moisture condition storage in the watershed soil permeability Peak Rate of Runoff - correct answer,,,,Q p as cubic feet per second cfs Time - correct answer,,,,Time of Concentration (Tc) is the time it take runoff to travel from the hydraulically most distant point in the watershed to the design point. The time of concentration is computed by summing all the travel times for consecutive components of the conveyance system Travel time - correct answer,,,,Travel time (Tt) it takes runoff to travel from one location to another in a watershed

sheet flow - correct answer,,,,flow over the upland area of the watershed where there is no defined channel or watercourse. Shallow concentrated flow - correct answer,,,,occurs once flow begins to flow rills. This generally begins within 150 feet of the onset of runoff and seldom after 300 feet of sheet flow channel flow - correct answer,,,,open channel flow occurs where channels are visible on aerial photos where blue lines exist on USGS quad sheets or channel existence can be verified in the field. Mannings equation generally used to predict velocity for channel flow Peak Discharge - correct answer,,,,qp = qu x A x Q x Fp qp= peak discharge qu = unit peak discharge A = watershed area q = runoff in watershed inches Fp = adjustment for watershed storage Soil Permeability - correct answer,,,,Soils are classified into hydrologic soil groups (HSG) to indicate the minimum rate of infiltration obtained for bare soil after prolonged wetting. The HSGs are one element used in runoff curve numbers. The infiltration rate is the rate at which water enters the soil at the soil surface. HSG also indicates the transmission rate (rate at which the water moves within the soil), which is controlled by the soil profile. Initial Abstration - correct answer,,,,Ia is the sum of the losses that occur before runoff begins. Hydrologic Soil Group A - correct answer,,,,Group A soils have low runoff potential and high infiltration rates even when wetted. They consist chiefly of deep, well to excessively drained sands or gravels and have a high rate of water transmission (greater than 0.30 in/hr) Hydrologic Soil Group B - correct answer,,,,Group B soils have moderate infiltration rates when thoroughly wetted and consist chiefly of moderately deep to dep. Moderately well to well drained solid

with moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission. (0.15 - 0.30 in/hr) Hydrologic Soil Group C - correct answer,,,,Group C soils have low infiltration rate when thoroughly wetted and consist chiefly of soils with a layer that impedes downward movement of water and soils with moderately fine to fine texture. These soils ahve a low rate of water transmission (0.05 - 0.15 in/hr) Hydrologic Soil Group D - correct answer,,,,Group D soils have a high runoff potential. They have very low infiltration rates when thoroughly wetted and consist chiefly of clay soils with high swelling potential, soils with a high permanent water table, soils with a claypan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very low rate of water transmission (0-0.05 in/hr) Disturbed Soil Profiles - correct answer,,,,A - sand, loamy sand or sandy loam B - silt loam or loam C- sandy clay loam D- clay loam, silty clay loam, sandy clay, silty clay or clay Drainage and Group D - correct answer,,,,some soils are in D because of a high water table that creates a drainage problem. Once these soils are drained, they are placed in a different group Planning Considerations for Runoff Management - correct answer,,,,Evaluate the site for Pre-development conditions Grading and construction Developed conditions Runoff considerations - correct answer,,,,Internal Site Conditions Divert and direct sediment laden water to BMPs Use existing or new permanent controls ASAP Design temporary controls as needed Site perimeter

Manage run on from areas Manage runoff from sites draining perimeter protect internal active inlets Surface Runoff Predictions - correct answer,,,,Runoff volume Peak rate of discharge isoheytal map - correct answer,,,,rainfall amounts provided through meteorological records maps provide 2 to 100 year frequency, 24 duration storms most of the US Storm Types - correct answer,,,,USDA categorized storm events into 4 types based on rainfall Divert Runoff (Diversions) - correct answer,,,,Earth Dike Perimeter Dike Water Bars Check Dams Temporary Swales Convey Runoff (Waterways) - correct answer,,,,Concrete lined channels Rock lined waterways Grassed waterway Grade stabilization structure slope drains Stabilize Outlet - correct answer,,,,Rock outlet protection level spreader paved flume Soil Stabilization - correct answer,,,,Erosion Control

combined with runoff management to limit or control erosion. Basic Principles that apply to establishing vegetation - correct answer,,,,stabilize slopes manage surface and groundwater i.e. seepage stockpile topsoil and reapply where possible Soil Stabilization - correct answer,,,,Erosion Control combined with runoff management to limit or control erosion. Basic Principles that apply to establishing vegetation - correct answer,,,,stabilize slopes manage surface and groundwater i.e. seepage stockpile topsoil and reapply where possible Soil Stabilization - correct answer,,,,Erosion Control combined with runoff management to limit or control erosion. Basic Principles that apply to establishing vegetation - correct answer,,,,stabilize slopes manage surface and groundwater i.e. seepage stockpile topsoil and reapply where possible Soil Stabilization - correct answer,,,,Erosion Control combined with runoff management to limit or control erosion. Basic Principles that apply to establishing vegetation - correct answer,,,,stabilize slopes manage surface and groundwater i.e. seepage

stockpile topsoil and reapply where possible Soil Stabilization - correct answer,,,,Erosion Control combined with runoff management to limit or control erosion. Basic Principles that apply to establishing vegetation - correct answer,,,,stabilize slopes manage surface and groundwater i.e. seepage stockpile topsoil and reapply where possible Soil Stabilization - correct answer,,,,Erosion Control combined with runoff management to limit or control erosion. Basic Principles that apply to establishing vegetation - correct answer,,,,Stabilize slopes Manage surface and groundwater Stockpile topsoil Retain natural vegetation Utilize suitable species Prepare an adequate seed bed Apply soil amendments as needed Mulching - correct answer,,,,application of plant residues or suitable materials to the surface. Mulching helps to conserve moisture and modify surface temperature fluctuations, prevent surface compaction or crusting, reduce runoff and erosion, control weeds and help establish plant cover on soils subject to erosion. Biotechnical slope protection advantages - correct answer,,,,usually less expensive than structural no specialized installation skills typically no heavy equipment needed

environmentally compatible natural aesthetic appearance provide wildlife habitat and cover PLS - correct answer,,,,Pure Live Seed PLS = germination % x purity / 100 Accretion - correct answer,,,,outward growth of bank or shore by sedimentation. increase of extension of boundaries of land by action of natural forces aggradation - correct answer,,,,general and progressive raising of a stream bed by deposition of sediment. Modification of the earths surface in the direction of uniformity of grade or slope by deposition as in a river bed. aggressive - correct answer,,,,refers to the corrosive properties of soil and water alluvial - correct answer,,,,deposits of silts, sands, gravels and similar detrital material that have been transported by running water arroyo - correct answer,,,,waterway of an ephemeral stream deeply carved in rock or ancient alluvium avulsion - correct answer,,,,a forcible separation, the sudden removal of land from the estate of one person to that of another, shift in channel location backing layer - correct answer,,,,layer of graded rock between rock riprap and underlying engineering fabric or filter layer to prevent extrusion of the soil or filter layer material through the riprap block - correct answer,,,,precast prismatic unit for riprap structure boil - correct answer,,,,turbulent break in a water surface by upwelling

boom - correct answer,,,,floating log or similar element designed to dampen surface waves or control movement of drift bore - correct answer,,,,transient solitary wave in a narrow or convergine channel advancing with a steep turbulent front, product of flash floods or incoming tides boulder - correct answer,,,,larges rock transported by a stream or rolled in the surf bulking - correct answer,,,,increase in volume of flow due to air entrainment, debris, bedload or suspended sediment camber - correct answer,,,,upward adjustment of the profile of a drainage facility under a heavy loading (usually a high embankment) and poor soil conditions, so that as the drainage facility settles it approaches the design profile capillarity - correct answer,,,,attraction between water and soil particles that cause water to move in any direction through the soil mass regardless of gravitational forces cavitation - correct answer,,,,erosion by suction, especially in the partial vacuum of a diverging jet celerity - correct answer,,,,velocity of a moving wave, as distinguished from velocity of particles oscillating in the wave cienega - correct answer,,,,swamp formed by water rising to the surface at a fault cobble - correct answer,,,,rock smaller than a boulder and larger than gravel cone - correct answer,,,,physio-graphic form of sediment deposit washed from a gorge channel onto an open plain, a debris cone also called an alluvial fan corrasion - correct answer,,,,erosion or scour by abrasion in flowing water

cradle - correct answer,,,,a concrete base generally constructed to fit the shape of a structure that is to be forced through earthen material by a jacking operation. The cradle is constructed to line and grade. crib - correct answer,,,,an open frame structure loaded with earth or stone ballast to act as a baffle in bank protection critical depth - correct answer,,,,depth of water in a conduit at which under certain other conditions the maximum flow will occur. These other conditions are the conduit is on the critical slope with the water flowing at its critical velocity and there is an adequate supply of water critical flow - correct answer,,,,that flow in open channels at which the energy content of the fluid is at a minimum. Also, that flow that has a froude number of one cutoff wall - correct answer,,,,a wall at the end of a drainage structure, the top of which is an integral part of the drainage structure. This wall is usually buried, and its function is to prevent undermining of the drainage structure if the natural material at the outlet of the structure is scoured by the water discharging from the end of the structure. Cutoff walls are sometimes used at the upstream end of a structure when there is a possibility of erosion at this point design discharge - correct answer,,,,quantity of flow that is expected at a certain point as a result of a design storm. Usually expressed as a rate of flow in cubic meters per second design flood - correct answer,,,,peak discharge of the flood associated with the probability of exceedence selected for the design of an encroachment in a FEMA Flood plain design frequency - correct answer,,,,the recurrence interval for hydrologic events used for design purposes design high water - correct answer,,,,flood stage or tide crest elevation adopted for design of drainage and bank protection structures Within the US, how much is spent on solving erosion problems annually? - correct answer,,,,3.3 to 13 bil in erosion

500 mill annually to remove sediment What did NURP study discover? - correct answer,,,,Tss major pollutant, heavy metals major pollutants in urban runoff Erosion rates 10-20 times higher at construction sites than u disturbed lands Tss impacts? - correct answer,,,,Changes in water chemistry Chemical influx to fish Algal growth Destruction of breeding areas Flooding possibilities Pollutants with construction activities? - correct answer,,,,Sediment Nitrogen/phosphorus ( fertilizers) Heavy metals Hydrocarbons Impact of construction to wetlands - correct answer,,,,Smother spawning areas Light pollution NEPA - correct answer,,,,National environmental policy act CZARA - correct answer,,,,Coastal zone act re authorization amendments 1990 RCRA - correct answer,,,,Resource Conservation and recovery act 1976 FIFRA - correct answer,,,,Federal Insecticide Fungicide and Rodenticide Act Criminal penalties - correct answer,,,,Negligent 2500 to 50k/day/violation