LIDAR for the identification of cultural resources

1. LIDAR for the identification of cultural resources Strong points and challenges

2. LIDAR stands for Light Detection and Ranging • LIDAR is available in field offices on your computer. • The LIDAR used here is a hill-shade GIS map layer. • It can detect subtle changes in topography that sometime provides information on ground disturbances done in the past and thus shed light on certain forms of cultural resources. • It is a valuable tool in detecting cultural resources such as burial mounds, Indian villages, trails, dugouts, earth lodges, and old mines.

3. Burial Mounds come in different shapes and sizes

4. Sometimes detecting cultural resources with lidar is obvious. Note the variety of prehistoric mounds. Knowingly disturbing mounds is a violation of state law, and in the past has led to violence. It is important for NRCS to know where these resources are located.

5. Mounds can sometimes be spectacular

6. Small Conical mounds are the most common type and are found throughout Iowa. The ones pictured here (upper center of the image) are partially buried by post Settlement alluvium (PSA). The next slide is a photo of these mounds.

7. Some conical mounds are difficult to detect because they are partially buried by post settlement alluvium (PSA) but show up clearly on lidar. People are standing at the tips of various mounds which are barely visible to the eye after the hay was mowed. If there was no PSA, these mounds would stand out. but in this condition, they would probably be missed by pedestrian survey.

8. Earth lodges are found in the western edges of Iowa

9. Earth Lodges when they collapse leave a circular depression (center of image).

10. Dugouts were an early form of pioneer house used for the first year or two of settlement in areas where trees for log cabins were in short supply.

11. Dugouts leave depressions

12. The same dugout shown on lidar (lower center of the image on the edge of the break). Dugouts were typically dug into the top edges of slopes.

13. Indian villages were sometimes fortified

14. A fortified village on lidar

15. A very well preserved unfortified indianvillage discovered by nrcsemployees. Note the lodge depressions in the left center of the image.

16. Iowa trails can often be seen on lidar, and the most famous is the Mormon Trail

17. Mormon Trail Through Iowa

18. The Mormon Trail in Iowa • The Mormon Trail in Iowa ran from Fort Madison to Council Bluffs. • It has left traces throughout much of southern Iowa. • These traces range from wagon ruts to cemeteries.

19. One of the most important way points of the Mormon Trail in Iowa was Mount Pisgah

20. When using the computer to look for cultural resources, don’t just use LIDAR. Check the GLO map below.

21. LIDAR overlain by the GLO map showing the actual ruts of the mormon trail compared to where the early surveyors mapped it (lower center of the image).

22. 1930’s aerial photo showing remnants of the Mormon Trail in lower center of the image.

23. Lidar of the pisgah grove area. Different kinds of images give you different information. Mormon trail ruts are present on lower center.

24. Ghost town dating to the 1850’s, Where wagon and stagecoach trails cross, and building basements are visible on west center of image.

25. Hundreds of previously undiscovered mounds are being found by NRCS employees using LIDAR

26. Iowa is one of the few states at the present time having complete lidar coverage. LIDAR has challenges as well as possibilities. For example, heavy tree cover can often hide ancient ground disturbances, and create false features that could be confused with cultural resources. There is a need for field checking when using this powerful tool. Because Iowa has had more of its area under cultivation than most other states, it was somewhat of a surprise to find out how many ancient cultural features were still identifiable with LIDAR. Iowa NRCS is in the process of creating a manual for Field Offices on how to use LIDAR to detect ancient cultural resources.