Sunday, March 4, 2018

HEC-1 Style Guide

Although HEC-1 is a dying program, it is still the standard in fast-growing Maricopa County, Arizona (home of the Phoenix metropolitan area). So it's worthwhile to share some style insights for HEC-1 modeling.

Guiding principles


1. Operations can only be 6 characters long. Be cryptically brief, avoid ganging character, and have a standard way to drop characters in a pinch.

2. Keep operation names unique. This seems obvious, but is violated surprisingly frequently in the case of diversions.

3. On schematic maps, use arrows and line labels instead of bubbles for diversions and reach routing. Diversion and reach routing bubbles end up confusing things more than helping.

4. Start operations with an least one letter and end with numbers to make text searches easy.

5. Use a single unique letter of the alphabet to denote each of the following operation types:
a. Sub-basin/watershed/catchment
b. Combine
c. Reach routing
d. Storage routing
e. Diversion main leg
f. Diversion split/divert/retrieval leg

6. Give each diversion split retrieval leg the same name as the saved hydrograph being retrieved
KK M652
KM SPLIT FLOW AT ELM AND MAIN
KM MAIN GOES SOUTH. SPLIT GOES EAST.
DT D652
.
.
.
KK D652
KM RETRIEVE SAVED HYDROGRAPH FROM ELM AND MAIN EAST
DR D652

7. Use KM records to explain what you are doing at each operation (hydrology info). Use asterisk comments to explain what you are doing to the file (changes, history of revisions, credits/blame, metadata).

Suggested naming schemes

W345 Watershed 345. It's popular to omit any letter for sub-basin operations. But text searches work better with a letter. Note below that the letter "W" is not carried through to other operations.
C345 Combine at concentration point 345
R345 or RC345 or R345.1 or R345A Reach (river) route the previous 345
R345B etc. Reach (river) route again
S345 Storage route 345
M345 Diversion to "D345" resulting in Main leg M345
D345 Retrieved diversion "D345" from M345
M345S Diversion to "D345E" resulting in Main leg M345S
D345E Retrieved diversion "D345E" from M345S

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