I hope you'll pardon if I'm woefully outta touch w/ current details.
"Terrain" is the proper word, SW. Unfortunately, the tools I'm most familiar with don't have that level of detail for this area. There maybe something available locally. The best information we have for this type of consideration, IMHO, are the pics of the area AFTER it had been cleared by LE.
IIRC, in the photos there is at least one pic that shows the area cleared and what probably serves as the low-point drain, albeit not man-made, out of this area. It seems to run from the northwest corner in a diagonal arc toward the east and south (on the grid drawing it would run from the mid-right side to the mid-top of the drawing - very roughly). I'll edit & add to this post if I can find.
Agree w/ another poster that his area is not fast draining, however, one should note that the flooding & receding water still has a
substantial effect on the dispersion of loose items. The presence of vegetation also has a significant effect. While I can't speak specifically regarding the effect on human bones, I grew up on a farm located on a major river where the fields flooded & receded each Spring...complete with slow draining 'swampy' areas. Sooo...I've spent many, many, many days cleaning up after slow draining flood water and observing the debris it leaves behind.
Trying not to be disrespectful in anyway (bless her heart
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
)...here's one scenario based on the relative bones positions on the grid:
1) "AREA A": The heavier skull along with the arms (radius & ulna), hands and the lower portion of the legs (fibulas) (below the knee) and feet remained essentially in the bag(s) for the duration from the time of disposal to discovery. Note: No tibias listed (tibias are paired w/ the fibulas).
2) "AREA F": After much time & decomposition the trunk and upper legs were first transported** to the position approximately 6-8 feet south of the bags (w/ skull and arms remaining in bags). This is suggested by the heavy ilium (largest portion of the pelvis) and both femurs (long leg bones) and clavicle (collar bone) being found together in this location.
3) "AREA H": The balance of the trunk (ribs, left scapula) being an additional 6-8 feet south may be the result of a subsequent transport event.
4) "AREA I": The remaining ribs & vertebrae being an additional 6-8 feet to the south and west appears to be in the general direction of the low-point drain would be from them partially floating in the receding water.
**While we don't know the detailed history of flooding/receding between June-Dec '08, we do know that Tropical Storm Fay passed through mid-August with ~3 consecutive days (~12" in 24hrs per this source
http://orlando.about.com/b/2008/08/22/rainfall-from-tropical-storm-fay.htm) of rain. This may have very well been enough water introduced into this area after 9 weeks of decomposition to have lifted the trunk as described in (2) above, with subsequent movement (3) being from later cycles or scavengers, and (4) from receding water.
All, IMHO, of course.
ETA: Rainfall est. for Fay. & "Area" designations as found in the topigraphical map p3513.