Glossary of Civil Engineering Terms

(used in land development)

Full Definitions

(click on term to see definition)

ALTA Survey

ALTA (American Land Title Association) Surveys are generally ordered prior to a real estate transfer, mortgage financing, or sometimes are requested for title insurance on a pre-existing site that has been generally used for commercial, industrial, or manufacturing. They provide a comprehensive and in depth picture of all aspects and features of the site: currently and historically. ALTAs require a significant amount of research and can take months or longer to complete.


After the construction is complete, we go back and create as-builts. We use construction plans in the beginning to create the project, we use as-builts to show any changes we made during construction.

Boundary Survey

A survey of a parcel/s of land that show where any existing property pins are AND shows what pins were set.


A buffer is similar to a setback in that it's a specified and required distance. However, buffers are usually utilized to protect or separate one use or feature. Example - You may have a required buffer from an environmentally sensitive area. Or, buffers can be utilized to provide separation from two different zoning districts (i.e.: commercial from residential).

Construction Plans

These are completed after the preliminary plat generally.They literally tell the contractor how to build the development. They show specific elevations of various surfaces, slope percentages, how much and what type of dirt needs to be moved, where to move it to, vertical and horizontal locations of utilities (sanitary, storm, water main, fiber optics, phone,cable, electric, gas etc.), sizes and materials of pipes etc. Construction plans are very in depth and detailed! Most construction plan sets are multiple pages....and they have a tendency to change during construction (See definition of As-built).

Final Plat

After the preliminary plat is approved by the governing bodies, then comes the Final Plat. They are similar to Preliminary Plats in that they show the lot configuration, roads and so on, but they do not show the details that a Preliminary Plat does. They do get approved by governing bodies and once approved, they get recorded in the County Recorder's Office. Once the Final Plat is recorded, you now have a legal conforming lot that can be sold or transferred to a different party.


The property bordering the street used for the property address


Letter of Map Amendment/Letter of Map Revision - When a structure (house, building etc.) is located within a floodplain on a FEMA map,that does not necessarily mean that it is at an elevation where it will flood.Lines on floodplain maps are general. A surveyor can go out and shoot in the location of the lowest opening of a home or building and then compare it to the exact elevation provided by the DNR. If the lowest opening is above the elevation the DNR says is floodplain level, then an engineer may be able to complete a LOMA/LOMR to certify the structure is not in danger of flooding.This is done mostly for insurance of finance purposes.


Area on a piece of property used for something other than a building - for now.

Preliminary Plat

A preliminary plat is a "proposed" schematic of a subdivided lot of lots. In essence the preliminary plat shows the lot configurations, roads, storm water basins, wastewater, contours and potential easements. Most of the time we need a topographic survey or at the very least LIDAR contours to do this. A preliminary plat is not recorded in the County Recorder's Office and they do expire! You can not sell lots after a preliminary plat is approved, you have to wait until after the final plat is recorded to do that.

Retracement Survey

A survey done to attempt to find the boundary line of a parcel of land. A retracement will show what property pins are existing, or not existing. Property pins are generally not set when a retracement survey is requested.


The request separation distance generally defined within an ordinance or zoning district. Example - The distance a building must be from a property line.

Site Distance

We use this when referring to traffic or placement of accesses/driveways. This is the required distance you must be able to see when you turn your head left or right while sitting in your vehicle. Site distance requirements are based on speeds.

Site Exhibit

Think of a site exhibit as more of a conceptual drawing or more along the lines of what a site "could be." This is generally more of a "pretty picture" used to market the idea to the governing body and financial institutions. No technical data, engineering or survey information is included in a site exhibit.

Site Plan

A site plan is created for one buildable lot to show how the building(s) will lay out on the site. This includes but is not limited to showing; engineered grades, utilities, lighting, sidewalks, accesses, traffic flow, landscaping, setbacks, storm water basins, traffic signals, etc. Site Plans are approved by governing bodies and construction of the building(s)cannot begin until this process is approved.

Specifications (Specs)

These are the written out specific instructions of how to build, what materials, exact sequences and directions. They are usually coupled with construction plans. In private land development they are usually replaced with "plan notes". These are written on the construction plans. Spec books are produced most often for municipal or government projects.

Topographic Survey

Topographic Surveys map the contours of the ground and existing features on the property's surface (or slightly above/below the surface (i.e. trees, buildings, streets, walkways, manholes, utility poles, retaining walls, etc.)

Topographic Surveys require require reference or fixed points (benchmarks) to which ground contours are related. This can be, for instance, information regarding surface and underground utilities, determination of required setbacks, etc.

Traveled Surface

This is the difference between right-of-way (ROW) and the actual road surface, the part you drive on. The ROW is often time much wider than the traveled surface.


A variance is a request to the Board of Adjustment (usually)to allow something that does not comply with the current ordinances. The general rule of thumb is the request has to be due to a hardship you have not created yourself. Example - If you are rezoning a property that has an existing building on it and the building does not meet setbacks, you can request a variance.


(click on term to see definition)


American Association of State and Highway Transportation Officials


Best Management Practice - used to manage either quantity or quality or both for storm water


Board of Supervisors


Corrugated Metal Pipe (as generally found in culverts)


Army Corps of Engineers


Department of Natural Resources


Federal Emergency Management Agency


Hot Mix Asphalt


Home Owners Association


Iowa Storm Water Management Manual


Low Impact Development


Light Detection and Ranging (contours established by flyover) - Generally less precise than a topographic survey


Not In My Backyard


National Pollutant Discharge Elimination System


Office of State Archeologist

P n' Z

Planning and Zoning


Portland Cement Concrete - a dense, strong material often used for high use and heavy traffic roadways


Reinforced Concrete Pipe

Secondary Roads

Roads managed by the County Engineer


Right of Way


State Historical Preservation Office


Statewide Urban Design and Specifications


Storm Water Pollution Prevention Plan


The act of conducting a topographic survey: the precise recording of land contours.

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