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. Note the stump under the 2x4 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.

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.

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.

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.

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.

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.

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.

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).

We believe strongly that water conservation is much more critical than most people recognize and water conservation will become equally as important as energy conservation.

To help reduce our water demands, we will use low volume plumbing fixtures and drought tolerant, native California species in our landscaping.  Importantly, we will have an underground cistern that will capture 100% of the rainwater that falls on our roof.

Rainwater Harvesting

Under the LEED-H guidelines, Water Efficient (WE) has three components:  Water Reuse (WE 1); Irrigation System (WE 2); and Indoor Water Use (WE 3).  At this point in our project, we need to ensure that the physical properties of our site will support our design (i.e., not constrain the elements in the design) so a cistern is critical.  The use of a cistern is covered under Water Reuse.

Water Reuse includes WE 1.1 Rainwater Harvesting System; and/or WE 1.2 Graywater Reuse System; or WE 1.3 Use of Municipal Recycled Water System.  There is a maximum of 5 points available in Water Reuse and up to 4 of those 5 points can be in WE 1.1 Rainwater Harvesting System.

We do not have a Municipal Recycled Water System and will not be utilizing a Graywater Reuse System; consequently, we need to focus on a Rainwater Harvesting System.

The design of our Rainwater Harvesting System will include 100% of our roof area and the cistern must be sized to hold all of the water from a 1-inch rainfall event.  Given our roof is 63’4″ by 63’3″ (almost a perfect squate), we have 4,006 sq ft of roof area.  For a 1-inch rainfall event, our roof will capture approximately 2,484 gallons of rainwater.

Cistern Requirements

Our property cannot support an above-ground cistern so we need to have a location for an underground cistern.  The swimming pool and existing trees at the back of the house limit our location to the front yard.  It would be great to have a cistern under our driveway but that would come at a significant cost.

Alternatively, we have some space at the East side of our front yard where we removed a Canary Island Pine tree.  Removing the stump will require an excavation, so it will make a feasible location for an underground cistern.  We will use the excavated soil to fill the remaining voids at the front of our house.

Our civil engineering team, from Bowman & Williams, were reviewing our alternatives and Casey Carlson recommended that we consider the CUDO System.  He was familiar with the CUDO System and though it could be integrated with our site easily.  We liked Casey’s design and recommendations.

CUDO System

The CUDO System is an innovative product that include 2×2 ft plastic cubes, which can be configured in a number of ways.  A bladder goes around the internal plastic cubes, creating the cistern.  The CUDO System could include a pump that can be connected to our irrigation system, thus reducing our water demands.

Given our space availability, Bownman & Williams recommended that we put in a CUDO System that is 4 cubes wide (8 ft) by 8 cubes long (16 ft) and 2 cubes deep, that is just over 24 inches below grade.  The underground cistern will have a capacity of 492 cubic ft, or 3,677 gallons.  This will allow our cistern to hold approximately 1.5 inches of rain.  Once the cistern is full, it will have three pipes to carry the overflow, via gravity, to our storm sewer.

The team from CUDO Stormwater Products, Inc. included Doug Allard, Ron Powers, Jon McDonald and Sue Lillo.  They tailored the design from Bowman & Williams and helped to establish the detailed specifications.

Site Visit by Sue Lillo

The sales representative for Northern California, Sue Lillo, was going to be in the area so we invited her to visit our site.  Bryan hosted her site visit and showed Sue the various features of the house.

Sue confirmed that the location would work and that she would ensure the product was available and delivered when we need it.

Sue Lilo, sales representative for Northern California, arrived at our job site and reviewed the features of our renovation project.

Sue standing on the stump, showing where the CUDO System will be located (below grade).