1. Elevation Hydrology Tools
“A streamlined and Simplified Approach”
Kent Peña
State GIS Coordinator
Adolfo Díaz
MLRA GIS Specialist
*special thanks to Peter Mead MN NRCS, he started it all!

2. The Nuts & Bolts
• The tools are just a toolbox…no install
• Leverage the use of clipping to an AOI to reduce data size
• Streamline the creation of flow direction, accumulation
and stream network derivatives
• Watershed delineation and associated attributes, area,
average slope, runoff curve number etc.
• Creation of pool storage layers
Overview of various unique python scripting solutions that
were used

3. “So, what is a Runoff Curve Number?”
The runoff curve number (also called a curve number or simply CN) is an
empirical parameter used in hydrology for predicting direct runoff or infiltration
from rainfall excess.
It is widely used and is an efficient method for determining the approximate
amount of direct runoff from a rainfall event in a particular area.
Runoff Curve Numbers are calculated based on land cover and hydrologic
soil group.