Best way to get elevation change

I'm fairly new to running a grader. We purchased a Deere 770b for use on our farm/ranch. I'm looking for the best tool to mount in cab to show elevation increase/decrease. We are wanting to build small dikes in our fields to hold/ catch snow and water. Getting a rough estimate of elevation changes should help us Any recommendation or ideas would be great. Not looking to spend a large amount. Thanks

Best way to get elevation change