Part 1: Establishing the Boundary
Have you ever wondered why the distance between the shoreline and the government boundary line varies around Hartwell Lake? Well, you’re not alone! This is one of the most frequently asked questions park rangers receive from adjacent landowners. The answer to the question is relatively simple, but can be somewhat complex to explain. Simply put, the U.S. Army Corps of Engineers boundary line is based on a contour or elevation. But because contours vary according to topography, so does the distance between the shoreline and the Corps boundary line. If you look at a topographical map for instance, you will notice that the contour lines are close together at some places and farther apart at others. The closer the contour lines are together, the steeper the terrain is at that location. In low-lying, flatter areas, contour lines will be farther apart. This is why the Corps boundary is generally closer to the shoreline in steeper areas of the lake and farther away in more gradually sloped areas.
I know, there are already some of you saying, “That’s not how it is in my backyard!” As is evident, this is a general description of the boundary line. Now let’s look at the historical and technical background for the establishment of the Corps line at Hartwell. Corps projects nationwide were authorized under different legislation, according to the time they were constructed.
Prior to 1953, land acquisition by the Corps projects was largely determined on a case-by-case basis. From 1953 to 1962, the Corps acquired lands primarily to
the 5-year flood stage (flood stages are estimated elevations of water bodies that could reasonably occur at specified time intervals). Lands above the flood stage
could be acquired when justified. This policy, known as the Eisenhower Policy, limited land acquisition to that required for operational purposes. Hartwell Lake was authorized as an Eisenhower project. The 5-year flood stage for Hartwell is 665 ft mean sea level (msl). The elevation at the top of the floodgates
is also 665 ft msl while the elevation of the earthen embankments is 674 ft msl. In a worst-case scenario, considering the inflow and outflow of water into the reservoir, Hartwell Lake could reach 674 ft msl. The 150-year flood stage is 668 ft msl and the 1000-year flood stage is 670 ft msl. Based on this information and the topography of the area, the prescribed purchase boundary for the Hartwell Project was set at elevation 670 ft msl.
Does this mean that the Corps line concisely follows the 670 ft msl contour? The
answer is NO! The 670 ft elevation was used as a basis or standard for establishing the Corps line. By using aerial photos and topographical maps, ground crews placed iron pins and concrete monuments at elevations intended to include land required for operational purposes. With few exceptions such as roads and creeks, the Corps boundary line runs in straight lines from one corner pin or monument to another. Because the Corps line runs straight from pin to
pin, the distance between the shoreline and the Corps boundary varies more so than a true contour line. In summary, the Corps boundary line was determined by congressional criteria based on flood possibilities and operational needs.
Part 2: Maintaining the Boundary
The boundary line around Hartwell Lake is simply a property line that designates the land purchased for the purpose of the Hartwell Project. Just as your property line delineates the property you are responsible for, the Corps boundary line delineates the land the Corps of Engineers is responsible for. As is the case with most private property, the Corps boundary is established with “monuments” – iron pins and concrete posts.
The Hartwell Project has 840 miles of boundary line designated by 9800 monuments. The line has been established by survey with each monument identified by coordinates (latitude and longitude). Additionally, each pin and monument is assigned a specific “pin number” and mapped 
accordingly.
The markings most familiar to adjacent landowners, in relation to the Corps line, are the orange marks on trees around the lake. These painted trees DO NOT designate the exact line, but rather “witness” or mark the general proximity of the boundary line. There are four separate symbols used that represent different information.
A brochure is available from the Hartwell Lake Office explaining these markings and their meanings. These markings have two primary purposes – to inform lake users and adjacent landowners of the approximate Corps line location.
Why is it important that adjacent landowners know where the Corps line is located? As stewards of the public land around Hartwell Lake, it is the Corps responsibility to maintain and protect the land that has been entrusted to us. Part of this stewardship includes annual surveys of the Corps line to identify
and resolve encroachments and to reestablish missing or damaged monuments. An encroachment is a structure or improvement that extends over, across, in or upon Corps managed land that has not been approved. Encroachment resolution typically requires the removal of the encroaching structure. Knowing where your property lines are – including the common boundary you share with the Corps – can prevent costly corrections. To prevent the possibilities of encroachments, we encourage all adjacent landowners to have their property surveyed by registered land surveyors prior to constructing homes, outbuildings, or any other improvements. Surveys should tie into the established Corps boundary. Park rangers are available (by appointment) to meet on-site to discuss the Corps boundary and provide documented boundary line information.
www.sas.usace.army.mil/lakes/hartwell