Freshwater Use in Las Vegas

When I mention ‘Las Vegas’, what comes to mind? What comes to my mind are impressive displays of fountains and magical bursts of water in a city that was built in an arid desert, but I also think that it is such a waste of water. 

 

 

Personally, I cannot put it any better than Tim Barnett (ScrippsInstitution of Oceanography): “It’s just going to be screwed. And relatively quickly. Unless it can find a way to get more water from somewhere Las Vegas is out of business. Yet they’re still building, which is stupid”.
In this blog, I want to explore where Las Vegas derives their water sources, how much water is used, and the impacts on these water sources.

Las Vegas City has a population of more than 600,000, but the Las Vegas metropolitan area accounts for more than 2 million people, and the population size is projected to increase to more than 3 million by 2042 (World Population Review, 2016). The large increase in population for the metropolitan area results in large demand and pressure for more water resources in an arid environment, thus misbalancing the demand and supply of water that the catchment can provide (Salvaggio et al., 2013). 

The Southern Nevada Water Authority (SNWA) derives their water sources from the Colorado river which flows into the Lake Mead reservoir behind Hoover dam, providing 90% of the water to the metropolitan area, however the Colorado river flows are declining due to droughts and climate change which is proving to be a huge challenge for water resource management with an increasing population and an expansion in the urban area (Salviaggio et al., 2012). Because of the decline in river flows, Lake Mead reservoir water levels has fallen to an all-time low of 1080 feet above sea level in the last 78 years (Icenhower and Dhar, 2015). Las Vegas uses up to 219 gallons of water per person per day and experiences an annual average of less than 13cm of rainfall (Dawadi & Ahmad, 2013). Hence, the combination of low rainfall levels, declining water levels, drought and climate change and an increasing population requires serious management and conservation plans if Las Vegas would hope to reduce the threats to their water security in the near future.

SNWA decided to build a third intake pipeline as a precaution to declining lake levels so that water can still be supplied to the city even if Lake Mead continues to decline to its lowest-record water levels (Locher, 2015). This does not appear to be a sustainable method to address the water decline, but rather a back-up plan which attempts to delay serious environmental concerns whereby the continued consumption of water from Lake Mead will eventually drain the entire reservoir. Furthermore, a $650 million pumping station will be built by 2020 to reach and draw water from the deepest depths of Lake Mead as an alternative water source to the declining Colorado river flows. Interestingly, declining river flows and lake levels should be a clear sign that the management of water resources in this catchment and its regeneration should be the number one priority. But instead, the SNWA committee and board chairwoman Mary Beth Scow insists that further pumps and pipes will need to be built to ensure a constant water supply to the city to further support the strong Nevadan economy (Walton, 2014). Castle et al. (2014) notes that while increasing demand would be placed on groundwater reservoirs in the Colorado River basin, these groundwater sources will not be able to meet future water demands and thus the long-term security of water will be significantly threatened.

Clearly, supply-side management policies can insofar provide a sustainable level of water supply into the city and so alternative methods. Dawadi & Ahmad (2013) suggests that a combination of water conservation and better pricing policies will enable water supplies to last longer into the near future. This study modelled conservation and policy scenarios to determine which methods would reduce demand for water. They found that both indoor-outdoor conservation practices such as managing water appliances (indoor) and converting turn grass into desert landscape (outdoor), and a price rise of water consumption by 50% had reduced water demand by 35% for 2035. These results are ideal for water conservation, but given that they are only model predictions, it may not translate very easily into management plans and practice. Indoor and outdoor conservation can be easily adopted whereas people may not agree or be willing to pay more for their water. Although, Salvaggio (2013) found that when people are knowledgeable about drought conditions and value the environment, then they are more supportive of water price increases.

Concluding thoughts:

Personally, I feel that a city like Las Vegas should not exist due to the impractical demands for water in a desert, which I believe to be a wasteful and unnecessary allocation of water resources. However, given that it still exists and it is unlikely that the city will be demolished just to conserve water, management policies and conservation is crucial for the future water security of the city and its inhabitants. Both demand and supply side policies should be considered so that the sustainability of water use can be fully maximised.

I would like to highlight an article by Jennifer Robinson in the Las Vegas Review-Journal (2015), who interestingly believes that there is no water crisis in Las Vegas because the city already has an effective management strategy in place, and so encourages the growth and expansion of the city. In contrast, the former general manager of the Southern Nevada Water Authority (in the video below) explains that Las Vegas is indeed facing a crisis and that the impacts of climate change can worsen this crisis. I implore you to read the article and watch the video, and determine for yourself if Las Vegas is using water sustainably and if Las Vegas can continue to expand economically and in population size with regards to water supply. 

Sustainable or Not?

The establishment of Las Vegas is one that always shocks me because it is a city that thrives and strives in the desert where drought is prevalent. Where does it get its water from? How much water does it use? Why does Las Vegas need that many fountains? My next blog will look at freshwater use from the Colorado River and Las Vegas and I will question its sustainability. For now, see the video below for a brief introduction to water use and Las Vegas. 

Shrinking Freshwater Resources: Part II

Not only is freshwater resources from surface supplies are vulnerable to being overused and depleted, groundwater resources are equally vulnerable and are being increasingly used in many areas of the world and to the point of depletion. Groundwater depletion can be defined as the rate of natural recharge to the aquifer being less than the rate of abstraction and discharge (Wada et al., 2010). Wada et al. (2010) study explains that areas prone to high levels of groundwater abstraction include North-East Pakistan, North-West India, North-East China, the central valley of California, and central US to name a few. They found that total global groundwater depletion totalled to 39% of the total yearly groundwater abstraction, which is an alarming rate for our global resources to be depleted.

Causes for groundwater depletion is a result of the overexploitation of these resources for agricultural, domestic, and industrial purposes. For example, areas in the world which has little access or supply to surface freshwater resources use groundwater systems as an alternative. Climate change is expected to have a huge impact on rainfall patterns over Africa, causing some areas to experience more droughts and others more flooding. Africa highly depends on rainfall and surface water sources and with this core supply reducing, alternative sources like groundwater is expected to be further relied upon for agricultural, domestic and industrial use as an adaptive method to climate change (Taylor et al., 2009). However, MacDonald et al. (2012) has found that there is a limit to how much groundwater resources can be used to supply populations in Africa. The study found that for low intense use, a groundwater borehole must be able to provide >0.1 l s^-1 whereas urban populations or large commercial scale irrigation schemes will require at least 5 l s^-1. Hence it is important to recognise that while populations use groundwater resources as an alternative resource, it may not be sufficient to keep up with the increasing demand for freshwater resources e.g. from an increase in population in Africa, ultimately leading to the depletion of groundwater resources.
In countries like the United States, local groundwater supplies are depleted for hydraulic fracturing to recover fossil fuels. Hydraulic fracking requires large amounts of water, and in a period where demand for energy is high, alternative solutions like fracking are adopted to fulfil that energy need. And thus, groundwater resources are highly affected. Water used for hydraulic fracturing increased from 10 to 55 million gallons of water in Michigan (Burton Jr er al., 2014). Michigan is considered to have an abundant amount of groundwater resources, but the demand and need for energy will only push for hydraulic fracturing processes in other areas, and thus the groundwater resources in those areas are likely to be highly impacted too.
India is the world largest user of groundwater resources, but these resources are reaching unsustainable limits (World Bank, 2010). India is endowed with an abundance of groundwater resources but the depletion of this resource can be linked back to the green revolution. Surface water was highly used by many populations across India, however since it was not accessible, groundwater was used more extensively for agriculture and drinking purposes. 85% of drinking water in rural areas comes from groundwater supplies, and increasingly populated urban areas such as Delhi consumes almost 50% of groundwater (World Bank, 2010).

Impacts of groundwater depletion has wider implications and it includes not only the depletion of freshwater resources, but the quality of water will decrease as wells are being dug for more water, land subsidence will occur, streamflow depletion and the increased chances of sea water intrusion in coastal aquifers (Famigeltti, 2014). Hence the environment tends to suffer the consequences of this groundwater depletion. For example, a case study in the North China Plain exhibits these same consequences on the environment as well whereby cones of depressions have formed largely under the urban prefectures of Cangzhou and Hengshui, declining at a rate of 1.0 and 1.7 m/year (Changming et al., 2001). Also, land subsidence in the Xingang area of Tianjin affected the strength of the harbour structures and increased the vulnerability of this region to storms.
Coastal cities that relies on groundwater resources is at the risk of seawater intrusion and a great decline in the quality of drinking water. For example, a study by (Mtoni et al., 2012) has shown that in the city of Dar es Salam, Tanzania, shallow wells are dominated by sodium, calcium and chloride ions due to increasing seawater intrusion near boreholes located in the coast. Deeper aquifers are still more mineralised, but if the rate of groundwater overexploitation continues unsustainably, then these deeper aquifers are likely to deteriorate in quality as well.

Groundwater resources are just as important as surface water sources, and once over exploited to an unsustainable limit, it can be difficult to bring these resources back to its previous level and quality. The management of freshwater resources is highly important for human wellbeing, and agricultural, domestic and industrial use, although freshwater systems are generally isolated on regional scales and so regional scale management is required. Thus I would like to further explore how freshwater resources are currently being used and if it is managed properly, sustainable and without excess consumption of it.