We Dutch know a thing or two about altitude-related water challenges but now we’re applying our engineering expertise at the other end of the scale as we seek to help the world’s highest capital city, La Paz, counteract the effect climate change is having on its glacial water sources.
Shrinking glaciers lead to water rationing
La Paz in Bolivia is the world’s highest capital city and has historically been dependent on Andean glaciers for its water supply. However global warming has seen these glaciers receding at a worrying rate. On top of that, Bolivia faced a severe drought in November 2016 due to El Nino phenomena. This resulted in the declaration of a national state of emergency and water rationing for residents. To relieve future severe droughts, and make available quick new water supply sources, the Bolivian government has called for urgent assistance to alleviate the crisis.
Water rationing for residents in November 2016
Knowing the problem
We have been involved in water projects in La Paz for many years and whilst on a site visit for one such project our team witnessed first-hand the water rationing and state of emergency which saw schools and businesses close.
Thanks to our strong relationships with local water and governmental authorities and our in-depth knowledge of the country we managed to garner a comprehensive understanding of the problems and goals of the client and have as a result designed a solution which is tailored to those needs.
For the city and the area to be able to rely solely on rainfall vast improvements must be made in the management of the city’s water supply.
Evening out the supply
We all know the allegory of the swan, the elegant bird, progressing serenely through the water whilst below the surface cleverly adapted feet and legs pump away frantically. This is what our suggested scheme would seek to deliver for La Paz’s beleaguered water supply.
Currently the dams that feed La Paz’s water supply suffer from major fluctuations throughout the year so that they can at times be overflowing whilst at others they run dry. By using a variety of methods under the surface or behind the scenes – smart water monitoring systems, centralised and advanced control, treatment plant upgrades and infrastructure updating – we aim to deliver an efficient, constant steady flow of drinking water to the city and its surroundings.
Don’t throw the baby out with the bath water!
Of course, as engineers we enjoy a blank canvass but starting from scratch in a heavily urbanised area is impossibility. Our approach instead has been to work with existing infrastructure, plants and systems to improve and enhance their performance and improve the future resilience of the water supply.
Our plan comprises three major elements: the expansion and improvement of existing water treatment plant Pampahasi; the centralised monitoring and advance control of dam levels; the reduction of non-revenue water.
By introducing smarter monitoring and control solutions to the dams we can read out the levels, reduce water losses on these scarce raw water resources and avoid the scenario of having some dams run dry whilst others overflow. Our design implements an information centre where raw water resources data is transferred online. This element of the scheme will provide an effective early warning system that will enable the government to take timely water demand mitigating measures that will prevent a water crisis if the reservoir levels were to drop.
The smart water software will control the dam levels, water flows between the dams and the production at four existing drinking water plants. This will enable tighter control and reduce water losses.
Pampahasi plant. Photo: Tierra Plus
A resilient future
The information centre has been designed to allow the integration of future plants. In order for the city to truly build resilience the existing wastewater treatment plant Pampahasi must also be expanded and upgraded to provide greater capacity and more efficient processes. With projections suggesting that demands on the plant will have almost doubled by 2026 our design ensures capacity to meet this.
Efforts to reduce non-revenue water are usually focused around pipework and the repair of aging infrastructure – see my colleague Daniel Levelt’s recent blog on the subject. In addition to this, in Bolivia we must also look at administrative leakage and work to improve the database of customers and users in order to ensure more robust monitoring and predictions are possible.
The project is financed in an innovative way: Dutch funding is considered through the DRIVE program to a maximum of 35%, to be complemented with loan finance to a 100% financing package. Furthermore, water operator EPSAS made development funds available. With the ever greater demands being placed on the region’s fragile water infrastructure we hope to get to work soon on this lasting solution.
Author: Michel Riemersma