The regional RC&D has been working on a watershed project for several years now. The focus has been on projects (strip trials, water quality monitoring stations, habitat inventories, etc.) on sub-watersheds. They are now trying to figure out how to approach an entire watershed – 600k acres. This interest is driven by a number of factors. The lower part of the river is one of Iowa’s protected waters and is used fairly extensively for recreation. The watershed has more tile, open tile line intakes, LAFOs, etc. than one can count but yet from a global perspective, it is in fairly decent shape. And of course, we have some endangered species, unmapped coal mines from 100 years ago, ag drainage wells, etc. to deal with.

Discussions have revolved on how one gets a handle on a watershed. Three things have been identified: topography, land use – current and past, and acute issues.

            1) For topography/hydrology - high resolution LIDAR data will become available this Fall/next Spring. And they can obtain site-specific rainfall data from a University of Iowa project.

            2) For land use, they would like to scan all of the annual compliance images from annual FSA overflights for the entire watershed going back as far as possible (20 years but typically 30+).

            3) For stream and stream bank health, the proposal is to map the river using a pair of digital imagers set up for stereo imaging with image stabilizing lens feeding a couple of big hard drives. The imagers would be mounted on a gimbaled camera mount. We would like to use a high accuracy GPS system to map location. This whole system would be mounted on a"standard" 4 person  hovercraft. The use of a hovercraft lets one access the river all 12 months and haul people/equipment to where they need to be as opposed to a "convenient site near a bridge".

Questions

            Has anyone pulled a system together for either #2 or #3?

            Is there a proven slide scanner for this application?

            We’re thinking about scanning all of the old tile installation drawings while we are in USDA’s offices. Is there a best flatbed scanner? The GOM hypoxia expert panel made some interesting suggestions regarding tile lines.

            Is there software that can take scanned slide files and ortho-rectify/geo-reference them in an automated fashion? They’re projecting 1200 slides per crop year. times 20+ years.

            The river valley is deep (up to 180’ below the surrounding land) and relatively narrow for ~30 miles of its length (average width is ~1/4 mile). How do we deal with GPS and differential GPS signals? And to make matters worse, lots of trees. We can access surveyed reference points at bridge crossings and along roads which parallel the valley for installation of a differential transmitter if needed. Is there a dead reckoning system that would assist in filling in the gaps?

            Can one add a radar or lidar system to physically map the shape of the riverbank at low water?  The follow-up goal is to measure riverbank erosion and to figure out (tree toppling, otter slide cut, etc.) what initiates major erosion events. We know that it isn’t really caused by farmer’s farming too close to the bank?

            Can we use a simple sonar system to map the bottom profile of the river when the water level is up? The follow-up goal would be to measure “sediment” movement.