anchor.diff:  
       i = domain%nx(1)/2
       j = domain%nx(2)/2    
  -    model_vd = -1.0_dp * domain%U(i,j,3)    
  -    model_d = domain%U(i,j,1) - domain%U(i,j,4)
  +    model_vd = -1.0_dp * domain%U(i,j,VH)    
  +    model_d = domain%U(i,j,STG) - domain%U(i,j,ELV)
       model_v = model_vd/model_d
   
       theoretical_d = (domain%manning_squared(i,j) * discharge_per_unit_width**2 / bed_slope)**(3.0_dp/10.0_dp)
  
positive.code: 
  program uniform_slope
      use global_mod, only: ip, dp, charlen, gravity
      use domain_mod, only: domain_type
      use file_io_mod, only: read_csv_into_array
      use local_routines
      implicit none
  
negative.code:             do j = 1, domain%nx(2)
                  x = (i-0.5_dp)*domain%dx(1) - cx
                  y = (j-0.5_dp)*domain%dx(2) - cy 
                  domain%U(i,j,ELV) = y*slope
              end do
          end do
          ! Wall boundaries along the sides and top
          domain%U(1,:,ELV) = wall_elevation 
          domain%U(domain%nx(1),:,ELV) = wall_elevation 
          domain%U(:,domain%nx(2),ELV) = wall_elevation 
          domain%U(:,1,ELV) = wall_elevation 
  
          ! Stage
          domain%U(:,:,STG) = domain%U(:,:,ELV)
  
          ! Ensure stage >= elevation
          domain%U(:,:,STG) = max(domain%U(:,:,STG), domain%U(:,:,ELV))
  
          domain%manning_squared = 0.03_dp**2
  
  