We have received a few questions from competitors who are looking to understand the cost of existing solutions for preventing canal seepage.

We are expecting that your costs will likely be higher than the cost of existing solutions. Remember that cost is only 10% of your phase 1 score.  Note that costs should reflect the life-cycle of the solution and assumptions should be explained in as much detail as possible.  Significant upfront capital costs may be outweighed in the long run by lower annual maintenance costs or increased longevity.

Below, we have provided a benefit/cost analysis table for canal linings. This table is adapted from Reclamation (1999) to estimate the construction cost in the present day. 

Table 1. Benefit/Cost Analysis for Canal Linings (Adapted from Reclamation, 1999)

 

Type of Lining

Durability

(years)

Maintenance Cost

($/ft2-yr)

Effectiveness at Seepage Reduction (%)

Benefit/Cost Ratio

Construction Cost

($/ft2) (1)

Escalated cost--low                 

Escalated cost--high

Fluid-applied Membrane

10 – 20 yrs

$0.010

90%

0.2 – 1.8

$2.68

$8.30

Concrete alone (Shotcrete)

40 – 60 yrs

$0.005

70%

3.0 – 3.2

$3.68

$4.46

Exposed Geomembrane

20 – 40 yrs

$0.010

90%

3.0 – 3.9

$1.97

$2.93

Geomembrane with Concrete Cover

40 – 60 yrs

$0.005

95%

3.5 – 3.7

$4.66

$4.87

Note: (1) An annual escalation rate to estimate the construction cost to 2021 is assumed to be 3%.

There was an interesting article published last week that discussed the cost of purchasing water and how the costs are absorbed by the end-user. In the example provided from the Westlands Water District in Fresno County, the end-user is covering the carriage losses which include loss due to seepage. Competitors in the Water America’s Crops Challenge may find this an interesting discussion to understand the broader context of costs for water.