Little Cistern, Don’t You…

Post soundtrack: “Little Sister” by Elvis Presley

The east side of the old adobe house in town we affectionately call ‘Casablanca’ was sucking up water like a sponge and we needed a more permanent intervention to ensure our new adobe work inside would hold up for the next 80 years. We put in a triple defense system to help curb the surface water runoff from the highway on the north side. This included drainage channels and catchment ditches, a percolating driveway surface, and a berm running the greater width of the lot that closed the main driveway. With the east side driveway now closed to vehicular traffic, we could reconfigure the yard to be the place of rest for a 1,000 gal cistern to catch the roof runoff via french drain. Again, very little professional consultation here. No matter the methods, all the advice we were given aligned on the main idea to move the water away from the walls. Period. Read on to see what we did and find out if it worked…

The below grade construction and downward slope from the highway were keeping our adobe walls wet inside

We relied on the guidance and techniques as described in the book, Adobe Conservation: A Preservation Handbook, and worked to expose about 10 inches of buried exterior wall as we started in on excavating the new waterways.

It became apparent after a few seasons of rain and snow here that we had some low spots to mitigate in our water diversion plan. The property line also created some challenges as we needed to move water away from the building but not into the neighbors’ lots (or into the proximal high traffic areas). By way of circumstance, we phased in the work and started digging out for the French drain in December 2022. The solar pump was finally installed in March 2024.

Digging out the walls and prepping for french drain
The material we removed here was the start of the roadside berm to stop runoff from the street

It was at this point that we realized we had the wrong fabric to wrap the perforated pipe. We pulled out the landscaping fabric and replaced it with non-woven double punched geotextile before backfilling with reclaimed gravel from the driveway.

The original plan was to dig a small dry well to act as a catchment for the runoff coming out of the french drain, so we rented the jackhammer once we decided the compacted driveway was too much for hand tools. This idea was finally usurped by an upgrade to a full cistern system. There was some pretty intense discussion between Ben and I regarding how big to make this system based on our limited budget, time, equipment/manpower, and the tight space we had to work between the house and the fence. Once we compromised on the 1,000 gallon low profile tank, we knew at that point that some larger equipment was necessary to make the hole. Bring on the John Deere 26G mini excavator rental (any smaller a machine and we wouldn’t have made our dimensions; any larger and we would have been taking out some soffit or fence)!

Cool little treasure unearthed

We shopped for the tank at a variety of sources both online and locally. We did not have a flatbed trailer to haul it ourselves, so we were at the mercy of whoever would deliver. Online retailers offered no notable cost advantage to local outlets, but the delivery arrangements would leave us waiting longer than we wanted. Local suppliers would deliver more quickly at a premium to our location 90 miles out of the metro area, but their inventory was more limited. We chose the Norwesco polyethylene septic model because we did not intend to use the water for drinking. (Granted, in a SHTF scenario, we would not hesitate to run the green tank water through a Berkey filter and subsist.) Once we had it delivered by the good people from Winsupply in Albuquerque, we followed the instructions for preparing the base of the hole with level and tamped crushed material (screened from native soil onsite) and again were grateful for the extra hands of our dear friend Mark to help with the install on a clear blue sky day.

Looking inside to see if the clear tubing at the baffle wall is installed close enough to the bottom for draw to the solar pump
Filling in layer by layer and homemade riser for access

With the south end plumbed for solar pump fixtures on the outlet, the north side inlet was connected to the french drain. We had one little hiccup, however… The drain didn’t work!! In our testing before closing everything up, the water coming from the house-side channel was not entering the perforated pipe as it was installed. It was enough to make us sick. We knew the geotextile was penetrable, but it appeared that the perforations in the Home Depot standard flex pipe were not large enough to accept the runoff at the rate of our test (dumping 3-4 gallons from a bucket along the graveled channel). This was a completely devastating turn of events after all our time-consuming and labor-intensive effort. There was no way in hell we were going to unearth the pipe and replace it at this stage in the game and time of season (it was now late September). We needed to find a ‘good enough’ workaround and we did after some backwoods engineering hearkening back to our time setting irrigation dams in Western Colorado and running the spring water feed in Taos Canyon.

The originally planned T-connection out from the french drain was replaced with an improvised drip pan

We had to get a little crafty with our solution, using only materials we had on hand since we were under the gun to back fill and return the heavy equipment on time. We could see that the water still followed the earthen channel we dug to exit, so the slope was correct. We put a hole in the middle of a scrap piece of metal roof flashing and placed it under the defunct perf pipe to pickup the moving water. Then, we cut down a 5-gallon bucket to serve as a shallow collection pan that would catch the drip under the flashing. The drip pan was plumbed with a grate to receive the 4-inch solid flex pipe to the cistern. We had to make multiple adjustments to ensure the runoff was being picked up on the flashing and fed into the pan (and cussed plenty along the way), but we finally could see that the soil under the pipe at the access point was staying dry and we could hear that the flow was feeding into the tank. We felt that was a good enough water trap to close it up. The pan was filled with gravel to stabilize the connection and prevent splashing, and then we filled in the opening underneath with gravel by hand. We also laid in gravel around the black flex pipe before filling the hole and finishing the grade on top of the cistern. This was about as simple an irrigation system as they come, but it sure was painful to concoct it after our more sophisticated installation failed on launch. Another lesson in adapt and overcome!

A little creative dirt work to add some points of interest in the new landscape
These flagstones were dug out from where we installed the French drain and made for a mighty fine garden path

The hand built solar pump from Aquabarrel (now discontinued) was put into service just in the nick of time since the cistern ended up full after several months of good snowfall. And the people rejoiced!!

Now, we have the fun stuff on the way… Planting and watching it GROW!! From Plants of the Southwest, we threw out some native grass and wildflower seed mix and set in a few each of native Aspen, Four-Wing Saltbush, Apache Plume, and Three-Leaf Sumac. We’re hoping that the foliage will grow in and help to absorb more moisture and lock it up away from the house.

Starting a little grove of thirsty Aspens

This was one of the more ambitious and complicated projects for us yet since starting our journey at Sahalee in 2016 and taking on Casablanca in 2020. We had never attempted any kind of DIY at this scale and certainly learned by doing. Looking at the cost breakdown, the materials and equipment cost around $5,000 just for this part of the below grade mitigation. We saved a lot by using materials we already had on hand and estimated the labor to be about 100 hours. Could we have gotten the job done for $10K with a pro? Perhaps. Sweat equity and hands-on experience is certainly worth something. Having another off grid water source available is priceless.

One of our job site inspectors