Stream Horizontal Flow Distribution The code identifying the horizontal flow distribution in the stream cross-section. That is, whether the flow is evenly or unevenly distributed bank to bank United States Geological Survey, Surface Water User Group UNSP 1 true unspecified The horizontal flow distribution was not specified. EVEN 2 true even The horizontal flow was distributed evenly from bank to bank. UNEV 3 true uneven The horizontal flow was distributed evenly from bank to bank.