river being studied (generally at least two floodplain widttis upstream and 

 downstream from the mined site location). Photographic coverage is desired for 

 as many years as are available, but should at least include photos 20 or more 

 years apart for the evaluation of long-term changes. The photos can be repro- 

 duced to obtain slides as described by Brice (1971) or can be used in print 

 form as described below: 



I. Enlarge the photos to the same scale, whenever possible. Select three 

 or more identifiable features on each photo. Place an overlay over one photo 

 and mark the selected features on the overlay. Place the overlay over the 

 other photo(s) and match the features to these marks to verify that the scale 

 is the same. If the scales are identical, the river banks can be traced from 

 each photo on the same overlay (Figure A- I ) . The lateral migration can be 

 measured directly from the overlay. If the scales are not the same, the follow- 

 ing steps are necessary. 



2. Select two identifiable features on each of the photos and connect 

 these to form a baseline (Figure A-2). These features should be located near 

 the opposite ends of the photograph. 



5. Subdivide the baseline into 10 or more segments and draw lines perpen- 

 dicular to the baseline through each of the segment endpoints, extending 

 the line through the area for which the lateral migration estimates are de- 

 sired. Subdivide one of these lines and draw lines perpendicular to form a 

 grid pattern (Figure A-5). 



4. Prepare a similar grid to any desired scale on a sheet of paper. 

 Transfer bank locations at each grid square boundary from each photo to the 

 corresponding grid square boundary on the sheet of paper (Figure A-4). The 

 rows and columns can be numbered and/or lettered to assist in the coordination 

 of the transfer. 



5. Connect the points on the paper to show the bank positions as they 

 appear on the photos (Figure A-5). The smaller the grid is on the photos, 

 the more accurate the bank lines will be. Lateral migration can be measured 

 directly from this figure. 



85 



