Directions for Using the Vulnerability Ranking Spreadsheet – Surface Water
There are two spreadsheets for surface water – one for sources with zones defined, and one for sources
without zones defined (zones are optional). The list in the spreadsheets comes from the PCA checklists.
； Surface Water Vuln Ranking master list.xls, sheet “SW w Zones” or
； Surface Water Vuln Ranking master list.xls, sheet “SW no Zones”
For the list with zones, each PCA is listed four (4) times: Zone A, Zone B, Watershed (remainder), and Unknown.
For the list without zones, each PCA is listed two (2) times: Watershed and Unknown.
PCA risk points (Column C) have been assigned based on the risk of the PCA (VH, H, M, or L) for that zone.
To use the Vulnerability Ranking Spreadsheet follow these steps:
1. Conduct the PCA inventory.
2. Make a copy of the appropriate spreadsheet and give the new sheet a descriptive name.
3. On the new sheet, delete rows for any PCAs that do not exist in any of the zones. (Remember
that each PCA is listed 4 times).
4. Delete rows for PCAs that don’t occur in a particular zone (i.e. if the PCA exists only in Zone
A, delete the rows for Zone B, Watershed and Unknown).
5. For PCAs whose existence is unknown, delete the appropriate rows (i.e. if you have no idea
whether the PCA exists, keep the Unknown row and delete the others. Similarly, if you know
the PCA exists in Zone A but you aren’t sure about B and the remainder of the watershed,
delete the rows for B and Watershed and keep the rows for Zone A and Unknown.)
6. The remaining rows should represent all of the PCAs that exist or whose location is unknown
within the zones. (For some sources, especially in urban areas, this may still be a very long
7. Calculate Physical Barrier Effectiveness for the source. Insert the corresponding points
(i.e., H =1, M = 3, L = 5) into column E for all the rows.
8. Determine the Vulnerability Score in Column F (sum of columns C + D + E)
9. Sort the list by the Vulnerability Score, from highest to lowest.
10. For surface water, the source is considered vulnerable to all PCAs with vulnerability score ;
11. Shade these yellow (see the sheet “Sebastopol” for example).
11. Review the list. This is a good time to review the assessment with the water supplier. Items
a. Are there detected contaminants in the source water? What are the PCAs associated with
the contaminants? Are those PCAs at the top of the list? If not, move them there with a
note or asterisk.
b. What were the perceived biggest problems before doing the assessment? Are these PCAs
at the top of the list? Should they be?
c. Are there PCAs at the top of the list that don’t seem particularly important?
12. If there are any concerns with the vulnerability ranking, go back and review the PCA
inventory. Revise the inventory as necessary.
13. Revise the vulnerability ranking as necessary.
14. Print the final list, save to disk, and submit with the remainder of the assessment.