Flood Plain Maps

The Chester River is located on the Eastern Shore of Maryland and is part of the larger Chesapeake Bay watershed. The area is very flat with only small increases in elevation. The peninsula also known as the Delmarva Peninsula is facing a double threat when it comes to flooding. Climate change is causing sea levels to rise, which will affect these low lying areas more drastically. Second, the peninsula is actually subsiding as well. Combined it is estimated that the area is seeing sea level rise rates double that of the rest of the US - roughly 3.4 mm per year. This sinking has been happening since the end of the last ice age. The Laurentide Ice Sheet covered much of the northern United States and it caused the land to uplift. Since the glacial retreat, the crust has been slowly subsiding. It is hard to predict how much it will subside in total, but it is important for all of the Delmarva Peninsula to understand what is happening. Below you will find a few different maps showing various flood events and how that would impact the land area within the Chester River watershed. Current land use is not contributing greatly to increases in these flood events because the amount of pervious surface is relatively high. It is important though that the large amounts of agricultural lands are doing their part in ensuring stormwater capture is part of their work. It is also important for all property owners to make informed decisions that reduce stormwater runoff in order to benefit the overall watershed.

This map shows the floodplain for Queen Anne’s County. It was adopted by FEMA and is used by the community to determine flood insurance. Image courtesy of Sam Stanton, Queen Anne’s County GIS 2015.

The oldest flood plain map I came across. This is of the Upper Chester River watershed. It is showing the floodplain for a 100 year flood event. The aerial image was taken in 1975, and even then much of the town of Millington would be impacted by a flood of that magnitude. Source: United States Soil Conservation Service. (1980) Urban flood plain map, upper Chester River watershed, Kent and Queen Anne Counties, Maryland. Lanham, MD: USDA-SCS. [Map] Retrieved from the Library of Congress, https://www.loc.gov/item/82696113/.

These side by side maps are showing the flooding caused by an increase of 1 foot in sea level rise versus a 10 foot sea level rise. The amount of land and property loss is hard to comprehend. Source: Summary: Chestertown, Maryland USA. (n.d.). Climate Central. https://riskfinder.climatecentral.org/place/chestertown.md.us?comparisonType=place

My final images are courtesy of QAC GIS. This mapping tool is incredibly helpful because of all of the possible layers one can add on. The first image is just the base, I added property lines and elevation because this is my neighborhood. The map below takes into account the floodplain in a high flood state which thankfully is not near my property.