Post Fire Water System Workshop Notes
From the CPOA - August 5, 2008

To all -

Last night CPOA hosted a workshop regarding the water system threats that can be expected over the next few rainy seasons. The workshop was run by Barry Hecht of Balance Hydrological, Inc. who has studied how watersheds react to fire over the last 40 years (including the 1977 Marble Cone Fire). The following is a brief summary of the workshop. This summary should not be used a guide to preparing for the coming rains. This summary is solely intended to get people thinking about what is coming down the creeks and rivers and talking with water system operators experienced with working in Big Sur after a major fire.

Fire Aftereffects We Can Expect:

Sediment: According to Mr. Hecht, about ½ of the sediment that will flow through these watersheds in our lifetime will come down in the next few years. The first couple of storms will carry sediment loads from 8 to 15 times normal.

Flow Volumes: Because significantly less vegetation will be drinking water, expect river flows to be 1.5 to 2 times greater than you would expect for a given storm series. Moreover, summer flows should also be higher than usual. Expect a storm that delivers 1 inch to act like a storm that is delivering 1.5 to 2 times as much water.

Flow Rates: The sediment coming off the hills will make the watercourses sandier and smoother. The smoother water channels will allow water to flow quicker. This speed will cause the quick transfer of debris including wood.

Ash: A lot of ash will come down the watercourses (and potentially springs) for several years. Ash loads will be particularly high in the first few storm series. Ash makes a royal mess of water distribution systems. Ash can breed microbes within a water system. Moreover, chlorine reacts with ash to release Trihalomethanes. Mr. Hecht also mentioned that springs can carry ash as well, particularly if the spring waters travel through limestone.

Logs: Log jams will occur and will increase erosion as the water seeks to flank the log jam.

Microbes, Heat and Solubles: While these items can create issues in other regions, Mr. Hecht felt the items described above are of greater importance in Big Sur.

Planning for These Aftereffects:

Fire and its Aftereffects Happen: Understand that what is happening is part of the natural pulse of Big Sur.

The Next Couple of Years will be Different: Water systems will experience intermittent water supply, changes in taste, color, and odor.

Know Your Neighbor: Get to know your neighboring water systems now. Plan for how the two systems can help each other during an emergency. When attending to spring boxes or any part of the system, take a partner with you. The slopes and canyons will be very slippery from the ash and there will continue to be issues with rock fall and falling trees.

Create Storage: Create 10 days of water storage. While it may be hard for a large water system to create 10 days of central storage, individual storage can help (4,999 gallon water tanks, 2,500 gallon truck bed water tanks, 250 gallon individual water tanks, even 5 gallon containers). This allows for flexibility during the winter when the system may be down.

Ash: Be prepared to pull up water diversion equipment during storm series to limit the ash that can get into the water system. There is no clear answer on what to do if ash does get into a water system. Flushing the system with hydrogen peroxide was mentioned with respect to galvanized piping. Note, it is not known how hydrogen peroxide will interact with ABS piping. Another issue is whether systems which chlorinate should switch to UV in the event ash becomes a problem - even if UV is the best practical solution (this remains to be proven) there are regulatory issues associated with taking the chlorine off line.

PVC vs Galvanized: Galvanized pipe that went through the fire may be heavier due to the setup and hardening of scale within the pipes. It may be prudent to use a less expensive, easier to reconfigure pipe material like PVC for the next few years prior to investing in the more expensive galvanized pipe.

Do Not Implement Long Term Fixes Too Early: Given the dynamic state of the watershed over the next few years, it may be prudent to hold off system wide long term fixes/upgrades until after things settle down. Moreover, the fire can provide an opportunity to jump start long term water system planning.

It's a Great Time to Start a Garden: Given the high flows that are anticipated and reduced shade, it's a good time to plant.

Spring Box or Well: Barry's focus was on repairing what you have and he steered away from well drilling only because this may not be appropriate or feasible for many of the small systems. Also, well drilling has very different regulatory requirements then small spring box systems.

As I mentioned above, this summary is not sufficient to prepare folks for the coming rains. I am sending this to share information from the workshop. Talk with an experience Big Sur water system operator/engineer to confirm what should be done to your water systems and how to implement these changes.

Lastly, many thanks to CPOA's Board and Officers who are working around the clock to coordinate these community workshops, getting experienced experts on the ground to assess what needs to be done before October, and pushing for funding to limit erosion and landslides risks. I hope to see everyone at the Gala this Saturday ( www.bigsurfirerelief.org )

Kind regards,

Aengus Jeffers