Email correspondence regarding alternatives spreadsheet presented during the October 10 Plan For Water workshop
From: Dianna Suarez
Sent: Friday, November 10, 2023 8:37 PM
To: Jennifer Hanson
Subject: Written comment on Alternatives Spreadsheet
Hi Jennifer, I reviewed the spreadsheet and wanted to send a written comment.
It is an interesting list. Some of the proposals are currently ongoing, including meadow restoration, forest management, canal encasement and lining. While no specific volume is given, we know that the outcomes are very beneficial, and may make a huge difference. More data is needed.
The costs are hard to compare because interest costs are not included. Interest costs can sometimes double project expenses. Those costs affect some alternatives much more than others because the dam raises and Centennial have to use borrowed money while other alternatives can be ongoing for many years. And some may utilize grant money.
The dam raises include just the cost of the dam which may be appropriate for modest dam raises. Centennial includes just the cost of building the dam as well. It does not include buying the rest of the private property, cutting down all the trees, removing the houses and septic systems, replacing Dog Bar Bridge, and litigation. The cost of raising Rollins says $5,804/af and Centennial is $5,310/af, because of the size. At the same time the individual cost to customers for raising Rollins 50,000 af is $1,740/yr raw and $29/yr treated while Centennial is $3,502/yr raw and $59/yr treated, (double the cost), and then it could double again with interest payments. I imagine the 110,000 acre feet is excess, not affordable, and all that extra maintenance, regulations and infrastructure that goes with it will have even more cost.
It looks like you are taking the average unmet demand for each scenario which tops out at approximately 40,000 af. It looks like the drought contingency plan (32,213 af) can get you almost there at a cost of $500,000 for the year. This option has flexibility. Manipulating carryover storage also is close to the target at 30,000 af for the year. That is another flexible option. The canal automation estimate was for 2% to 5%, 2,500 to 6,000 af, whereas Otis said that PCWA saved 15% by doing this which would change the af to 18,000 af. Quite a difference. It looks like you could get by without building anything. By far the best option.
The sediment removal costs were prohibitive if you simply look at cost per af storage recovered. But that is not the whole story. NID built Rollins, Scotts Flat, and Combie. These facilities are your responsibility for safety and maintainance. There is an obligation to maintain storage because this was the purpose of the facility. Eventually these reservoirs will fill up with sediment if storage capacity is not maintained and you will lose the value of that facility, which is way beyond what it costs to dredge. Looking at cost per storage af is simplistic and too limited in scope. You need to consider the loss of value of the entire facility.
It looks like staff spent some time thinking about these alternatives, but there is still a lot of guess work here. It looks like a good start. It will be interesting to see what alternatives the Directors decide to analyze. Best wishes, Dianna