It’s another Throwback Thursday. Saylorville Lake and Dam are located in Central Iowa northwest of Des Moines, Iowa. The Saylorville complex was built to help with flood control and as a drinking water source for surrounding communities. At normal levels, the Saylorville reservoir stores 21.1 billion gallons of water with capacity at flood levels to hold 204.1 billion gallons of water.
Below are several resources if you are interested to learn more about this important structure north of Des Moines:
Welcome to another Throwback Thursday. Today we are going back into the archives to compare imagery from the first five Landsat satellites (all images are featured in natural color). Click on each image for a closer view.
Try to notice the differences in resolution and image quality between the different years.
Another thing to note is the wide seasonal variation between the images. All the images were from the same three week period in April. Some images are have snow while other years are very green.
Observe that the Des Moines River is swollen in the Landsat 4 -1983 image.
What changes do you notice in this Landsat time lapse video?
1) The areas of purple and white in the image are urban areas. Throughout the video they fill in the area from the bottom to the center. The pink areas are farm land.
2) Did you notice the increase in the number of retention ponds (dark blue specks in the urban areas) over time? Retention ponds are used to prevent flooding and provide for water storage in urban areas. As areas become urbanized there is often more surface covered in concrete, parking lots and buildings. There are fewer places for the water to flow directly into the ground.
3) Did you spot the golf course on the northern edge of the city?
This year we are celebrating 50 years of the Landsat earth observing satellite mission. Landsat data helps us observe changes in our communities and environment over time.
This year marks the 50th anniversary of the launch of the first Landsat satellite (July 23, 1972). To celebrate fifty years of earth observation, IowaView will be posting various images and gif documenting Landsat in Iowa and around the world. Check back regularly for new images and articles. #TimeLapseTuesday #ThrowbackThursday
USGS just released a Story Map summary wrapping up 2021 and the exciting developments with the Landsat mission including a newly launched satellite and 10 million scenes in the archive mark two high points.
IowaView staff have released the Cover Crop ID Toolbox and Handbook. This toolbox allows users to quickly identify possible cover crop fields using three Sentinel-2 images from the fall, early spring, and late spring downloaded from the Earth Explorer website based on field boundaries supplied by the user. On the project webpage you can download the toolbox which works with both ArcMap or ArcGIS Pro as well as the Cover Crop ID Toolbox Handbook that provides additional details about each step of the tool.
Today, Mike Daniels from the University of Arkansas will be presenting about how the Arkansas Discovery Farm is reducing nutrient loss, defining and building soil health, improving irrigation efficiency and edge-of-field monitoring of runoff. His statewide Extension efforts encourage agricultural producers to adopt conservation practices to protect natural resources and improve agricultural sustainability.
Today we are celebrating remote sensing, the study of the earth using secondary observations from instruments such as planes, kites, drones, satellites as an exciting and powerful educational tool to help us show changes over time.
This year the AmericaView/NASA team has put together a fun and beautiful educational poster!