Installing Our CUDO Cistern – Day 1

With the excavator in place yesterday, Bryan met the operator, Jose, on site at 8:00 am to dig the hole for our CUDO underground cistern.  We had a small window of time between storms so we wanted to get the CUDO cistern in place before the New Year.

Importance of Retaining Water on Site

As our population grows, the demand for fresh water continues to increase.  One of the key areas that needs to be addressed is reducing the demand for water.  This can be done through low-flow fixtures and toilets, landscaping that requires less watering, recycling water through greywater capture, and harvesting rainwater from the roof and non-permeable hardscape.

We worked with Casey Carlson, with Bowman & Williams, to design a system that would harvest 100% of the rainwater from our roof and the water from our hardscape.  In addition, we are on a ‘seasonal perched water table’ and must pump water from under our foundation for part of the year.

A key element of the system is our underground CUDO cistern.  It is 512 cubic feet and will hold 3,677 gallons of water.  A pump inside the cistern will connect to our irrigation system to use the water we collect for our landscaping.  If the cistern is full, the excess water will then go to the storm drain.

While there are other types of underground cisterns available, Casey recommended the CUDO cistern as it was compact and efficient in terms of underground space, modular so it would be easy to design, and flexible so it could address any unexpected issues during installation.  Importantly, it would be easy and fast to install.

The CUDO system is comprised on various modular components, which is designed on a 2 ft x 2 ft x 2 ft cube.  Our system was 2 units deep, by 4 units wide and 8 units long (4 ft deep, 8 ft wide and 16 ft long).  The system was placed three feet below grade.

We confirmed the location of our underground utilities on December 22, 2009 so we are good to go.  Also, we will receive nine LEED points under various aspects of the LEED-H program.

Removing the Stump

As part of our project, we removed a large Canary Island Pine tree.  This tree was at the southeast coner of our property and was planted in 1969 by the developer, Eichler and Associates.  This fast-growing tree had served its purpose and was now blocking sunshine in the winter, when we require solar heat gain, and didn’t provide any shadown during the summer, when we have too much solar heat gain.  Cold in the winter and hot in the summer.

We removed the tree on December 13, 2008 but did not remove the stump since we planned to do so when installing our CUDO cistern.  Since the CUDO was going in, the stump had to go.

Jose assessed the situation and dug down on each side of the stump, removing the roots.  Then, he deftly pulled the front, and then the back, of the stump.  Within 18 minutes, the stump was sitting on the driveway.

Excavating for the Cistern

Having cleared the area, Jose then excavated the hole to width and depth, as we had staked it earlier.  We used 16 ft studs to meaure the length, and 8 ft studs to measure the depth and width as we excavated.  Jose distributed the soil around the machine, placing it so he could backfill the hole quickly after the CUDO cistern was in place.

Assembling the CUDO Sytem

As Jose was excavating the hole, our friends from Kristar arrived with the CUDO system.  Don Allard, the CEO arrived with Gary Jones, VP Field Operations (Sue Lillo, our sales representative for Northern California was enjoying a vacation and couldn’t be on site).

Don and Gary were here to ensure the system was installed as planned and to document the installation procedures for this new product.

While Bryan was working with Jose on the excavation, Don and Gary unloaded the 67 individual 2 ft x 2 ft CUDO cubes and snapped them together.  The CUDO system was staged on the street so it would be ready to position in the hole when Jose completed the excavation.

Installing the CUDO System

After the excavation was completed, we put down sand to form a level base for the CUDO cubes.  After marking the centerlines with washable paint on the soil and waterproof membrane, we placed the membrane in the excavation and folded it so the bottom level of 32 CUDO cubes could be installed.  With the foundation level in place, we put the second level of CUDO cubes on and then wrapped the waterproof membrane over the top of the CUDO system, just like wrapping a present.

Given the forecasted rain for tomorrow, we decided to take a break and complete the installation on Thursday, December 31, 2009 (and finish early!).

The location of the underground CUDO cistern was staked and marked, and double cheded for accuracy.

The location of the underground CUDO cistern was staked and marked, and double cheded for accuracy.  Note the stump under the 2×4 in the center of the photo.

To make the measuring easier and faster while we excavated, we used 16 ft studs and 8 ft studs to identify where we needed addtional excavating.

To make the measuring easier and faster while we excavated, we used 16 ft studs and 8 ft studs to identify where we needed addtional excavating.

This is the first dig at the stump, which must be removed so we can excavate for the CUDO underground cistern.

This is the first ‘bite’ at the stump, which must be removed so we can excavate for the CUDO underground cistern.

Jose is taking the second 'bite' at the stump, severing the root system on either side of the stump so he can remove it.

Jose is taking the second ‘bite’ at the stump, severing the root system on either side of the stump so he can remove it.

With the roots severed on each side, Jose was able to lift the stump and shake the dirt from the root system.

With the roots severed on each side, Jose was able to lift the stump and shake the dirt from the root system.

After starting 18 minutes ago, the stump is now sitting on the driveway.

After starting 18 minutes ago, the stump is now sitting on the driveway.

The frames for the modular CUDO system arrived so they could be unloaded and assembled on the Jose is taking the second 'bite' at the stump, severing the root system on either side of the stump so he can remove it.

The frames for the modular CUDO system arrived so they could be unloaded and assembled on the Jose is taking the second

With the stump gone, Jose started digging on each side of the hole, to the limits of where we needed to excavate.

With the stump gone, Jose started digging on each side of the hole, to the limits of where we needed to excavate.

Jose, operating the excavator, makes it look easy. He was the operator that excavated the lower level in December 2008.

Jose, operating the excavator, makes it look easy. He was the operator that excavated the lower level in December 2008.

We measured the dimensions of the excavation periodically.

We measured the dimensions of the excavation periodically.

Doug Allard (left), Carlos Torres (center) and Gary Jones (right) with the assembled CUDO system on the street.

Doug Allard (left), Carlos Torres (center) and Gary Jones (right) with the assembled CUDO system on the street.

After the excavation was to the correct depth and dimensions, we put a layer of sand at the bottom to make a flat and level base for the CUDO frames.

After the excavation was to the correct depth and dimensions, we put a layer of sand at the bottom to make a flat and level base for the CUDO frames.

A surprise inspection!

A surprise inspection!

After the waterproof membrane was in place, we installed the two layers of 16 CUDO frames in each layer and then wrapped the waterproof fabric over the top. This photo is looking South, towards Via Sereno.

After the waterproof membrane was in place, we installed the two layers of 16 CUDO frames in each layer and then wrapped the waterproof fabric over the top. This photo is looking South, towards Via Sereno.

This is the view looking North, towards the house. The supply lines will go in the CUDO frame on the left and the pump will go in the CUDO frame on the right (so we can irrigate our landscaping with the water in our cistern).

This is the view looking North, towards the house. The supply lines will go in the CUDO frame on the left and the pump will go in the CUDO frame on the right (so we can irrigate our landscaping with the water in our cistern).

2 Comments

  • I have one question. What are the requirements for soil types and/or compaction requirements for the backfill placed to bring the area back to original grade? Please advise. Thanks.

  • Bryan says:

    In our juridiction, we don’t have any required compaction and our landscaping plan is to bring the area back to the original grade. However, we personally want to bring compaction to at least 90% using the original soils. We want to limit the cracking and settling of soil after the fact. This is from our soils report:

    ——————
    5. Stripped areas should be scarified to a depth of about 6″, water-conditioned to bring the soils water content to about 2% above the optimum, and compacted to a density equivalent to at least 90% of the maximum dry density of the soil according to ASTM D1557 (latest Edition).

    6. Fill should be placed in thin (8″ loose), horizontal layers and then water-conditioned and compacted, as given above.
    ——————

    Helping us is our project timeline, which allows approximately 14 months, and two rainly seasons, after backfilling the location. Currently (August 2010) we are now excavating around the CUDO and putting in the water inlet and outlet (overflow) connections. We are compacting the soil to >90%, where possible, in all the trenches with hand-operated compactors.

    Hope this answers your question.

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