Prism Mesh V1b
This mesh is translated to zero coordinate:
define XTRANS 360600.
define YTRANS 3973000.

This fixes negative volumes by flipping triangluated surface up.
Also modified top material 1 to have 2 cells instead of 3.

Unstructured stacked prism Mesh
River 1 meter wide (same elev across river elements)
River buffer 1 meter wide
The River node elevations are interpolated from a center line DEM
Triangulation from .5 to 60 meters away from river

This is a first iteration triangulation using nicely formed polygons.
Improvements on the triangulation will be based on the model results.
Issues to look at:
  Are the river faces oriented correctly for flow?
  Is the river positioned within the topology correctly for flow?
  What is the effect of river 1 cell wide, impact where there are more?

The triangulation can be improved:
Use smarter refinement to reduce the total number of elements.
remove fan effects along parts of the river
break triangles inside branch intersects
improve smooth transition from small 1 meter cells near river to the 60 meter at boundary
improve triangulation along boundary to avoid mesh effects
See if triangulation of river can be improved to ensure single cells across width.
Consider different river strategy, such as dropping elevation at river.


Title: LAGRIT TO EXODUS                                                         
number of dimension:               3                                            
number of nodes:             1301690                                            
number of elements:          2334780                                            
number of element blocks:          2                                            
number of side sets:               6                                            

Materials (Total 9 cells vertical):
1 2 cells .25 thick
2 3 cells .75 thick
2 4 cells 2.0 thick

ExodusII: Done writing to ExodusII file: prism_fs.exo 
Exodus side sets:
  1 bottom            259420 faces
  2 top full          259420 faces
  3 all sides           8244 faces
  4 top river           6815 faces
  5 top river buffer   13634 faces
  6 top not river     238981 faces

Mesh stats:

      MIN              MAX              LENGTH
X  -4.975466309E+02  2.124468018E+03   2.622014648E+03  
Y  -6.834048462E+02  1.823483887E+03   2.506888733E+03   
Z   2.726891950E+03  3.323518000E+03   5.966260499E+02   

Volume   minmax: 1.736929065E-02  4.100583947E+02
Edge Min minmax: 1.250000000E-01  5.000000000E-01
Edge Max minmax: 7.483000780E-01  5.506619899E+01

Check for zero volumes:
rmpoint/zero_volume/1.e-7                                                       
   0 points removed and 0 elements removed.                      
   The point count is     1301690.                                            
   The element count is   2334780.