CSLB Land Development Engineering flashcards

34 cards. Read the term and the definition here. The deck at the top of this page is optional.

Floor Area Ratio

Ratio of gross building floor area to net lot area. Used by zoning to control building intensity independent of lot size or use type.

Dwelling Units per Acre

Density measure equal to the number of residential units divided by the net developable lot area in acres. Common zoning metric for housing capacity.

General Plan Consistency

Legal requirement that local zoning and land-use decisions be consistent with the jurisdiction's adopted general plan. Inconsistency can invalidate a permit approval.

Hillside Ordinance

Local regulation triggered by average site slope, typically over 15 percent, imposing reduced density, grading limits, and design standards on steep terrain.

Parkland Dedication

Requirement that new residential subdivisions dedicate land for parks, commonly 3 to 5 acres per 1,000 residents, or pay an in-lieu fee.

Rational Method

Peak flow formula Q = CiA, where C is runoff coefficient, i is rainfall intensity in inches per hour, and A is area in acres. Valid for small urban catchments.

Time of Concentration

Travel time for runoff from the hydraulically most distant point of a catchment to the design point. Used to select rainfall intensity for the Rational Method.

Average End Area Method

Earthwork volume formula: (A1 + A2)/2 times the distance L between cross sections. Approximates cut or fill volume between stations.

Prismoidal Formula

Volume = L/6 times (A1 + 4Am + A2), where Am is the mid-section area. More accurate than average end area for varying sections.

Freeboard

Vertical separation between the design flood elevation and the lowest finished floor or structure. Typically 1 to 2 feet to account for uncertainty.

Standard Proctor Test

ASTM D698 laboratory compaction test using a 5.5-lb hammer. Establishes maximum dry density and optimum moisture content for soil.

Modified Proctor Test

ASTM D1557 compaction test using a 10-lb hammer and greater energy. Yields higher maximum dry density and lower optimum moisture than Standard Proctor.

Relative Compaction

Field dry density divided by laboratory maximum dry density, expressed as a percentage. Typical structural fill specifications require 90 to 95 percent.

Expansive Soil

Soil with high plasticity index that swells with moisture and shrinks when dried. Requires overexcavation, lime treatment, or moisture conditioning before construction.

Allowable Bearing Capacity

Maximum soil pressure a foundation may impose, determined by the geotechnical engineer. Common values for native soils are 1,500 to 4,000 psf.

Stopping Sight Distance

Sum of perception-reaction distance and braking distance. Must be provided along a roadway so drivers can stop before a hazard.

Superelevation

Pavement banking on horizontal curves that helps resist centrifugal force. Combined with side friction, it determines the minimum safe curve radius.

Vertical Curve K Value

Length of vertical curve divided by the algebraic grade change. Relates curve length to stopping sight distance for a given design speed.

Cul-de-Sac Turnaround

Dead-end street terminus allowing vehicles to reverse direction. Commonly requires a 50 to 60 foot diameter right-of-way.

Hazen-Williams Equation

Empirical head loss formula for water mains: hf = 4.73 L Q^1.852 / (C^1.852 d^4.87) in US customary units, with C as roughness coefficient.

Residual Pressure

Pressure remaining in a water distribution system during fire flow. A minimum of 20 psi is commonly required to protect against contamination and collapse.

Backflow Prevention

Device such as an RPZ or double check valve installed at cross-connections to prevent contaminated water from entering the potable supply.

Manning's Equation

Open-channel flow formula Q = (1.486/n) A R^(2/3) S^(1/2) in US customary units. Used for sewer, storm drain, and channel capacity.

Self-Cleaning Velocity

Minimum flow velocity of about 2 feet per second in sanitary sewers that prevents solids from depositing. Maximum is about 10 feet per second.

Infiltration and Inflow

Groundwater and stormwater entering sanitary sewers through defects, joints, and illegal connections. Added to design flow for capacity sizing.

Detention Basin

Storage facility that temporarily holds stormwater and releases it slowly. Reduces peak outflow to pre-development levels using stage-storage-discharge routing.

Base Flood Elevation

Water surface elevation of the 100-year flood. Used to set minimum finished floor elevations and floodplain development restrictions.

Inlet Control

Culvert flow condition limited by the entrance geometry rather than downstream conditions. Headwater depth depends on inlet area and shape.

RUSLE

Revised Universal Soil Loss Equation: A = R K LS C P. Estimates annual soil loss from rainfall erosivity, soil erodibility, slope, cover, and practices.

Silt Fence

Fabric barrier staked on contour downslope of disturbed areas, with the bottom keyed into the ground, to trap sediment from sheet flow.

Check Dam

Small structure placed across a swale or ditch to reduce flow velocity and promote sediment deposition. Often built of rock, gravel bags, or logs.

SWPPP

Storm Water Pollution Prevention Plan required under the NPDES Construction General Permit for sites disturbing one acre or more. Describes BMPs and inspections.

Section 404 Permit

Clean Water Act permit issued by the US Army Corps of Engineers for discharge of dredged or fill material into waters of the United States.

CEQA

California Environmental Quality Act. Requires environmental review and disclosure for discretionary projects, with mitigation of significant impacts where feasible.