Preliminary Research Question: Is River Restoration Profitable?

Can river restoration be sold as an investment for water users? In other words, can restoration activities be justified by a reduction in water management costs downstream? Initially, I considered studying the financial costs of all water users downstream but I may need to focus on water treatment facilities since they are the largest water user with the highest expenditures.

To answer my question, I must understand the relationship between the water quality and treatment cost. If one could establish this relationship, one might find that a marginal improvement in water quality could lead to significant reduction in treatment costs. Since the Llobregat is highly polluted (low water quality), my initial assumption is that the treatment facilities are probably operating on the higher and more expensive end of this relationship.

Of course, specifying the relationship between water quality and treatment cost will not be easy. There are several obstacles. For example, there might be thresholds associated with certain contaminants which would create a step function. Another challenge will be defining “water quality” or “water pollution”. Both terms are comprised of many variables, often in different units. Similarly, cost data may fluctuate over time for reasons independent of water quality.

Studies have found that cleaner surface water can reduce treatment costs, although it is unclear by how much. One study in Texas found that a 1 percent increase in turbidity was associated with increased chemical cost of 0.25%. Furthermore, when comparing the presence or absence of a contamination index, the presence of contamination increased the chemical cost of water treatment an additional USD $20 to a total of USD $95 per million gallons (3,785 m3) (Dearborn 1998). More information on the total cost of water treatment would be necessary to assess the relative magnitude of these values. Also, one cannot expect to find the same level of savings as in the well known example of New York City drinking water because most urban areas already have constructed water filtration systems (Thompson 2007).