Citizen supported ground water monitoring in Tulum / Mexico

Tulum is a Mexican town, located at the Caribbean Coast of the Yucatan peninsula, well recognized but not crowded by tourists and famous for its Mayan ruins and cenotes. There are species-rich lagoons and wetland in the nearby Sian Kaan bio-reserve. The main water flow system is hidden in the karstic underground. Local population uses the water through private wells or the puplic water supply, which operates strong pumps in few cenotes. The vast underwater cave network is also important basis for touristic cave or cavern diving and snorkelling as well as the study field for exploration divers and numerous international scientific collaborations. The big karst water regime is only visible through scattered cenotes, most of them clear, so there is no obvious indication for degrading water quality. Hence, the public interest remains at low level. However, the fresh water resource is concentrated in a top layer, only several meters thick beneath the town, and thinning to zero at the shore - beneath the fresh water layer there is sea-water. The fresh water is endangered by urban development increasing demand, imperfectly sealed sewage systems and waste deposits prone to leaks as well. Therefore, pollution threatens the fresh water resource, the nearby Sian Kaan bio reserve, and important touristic income. Dives in the conduit system beneath the city and first analysis of wells, cenotes and lagoons conducted in course of the projects Xplore and the Xibalba already show indication of the mentioned threats and the need for continuous monitoring the waters condition. The realization of an adequate monitoring network can be accomplished with support of the local population reached through schools. Pupils will be provided basic knowledge and skills to do chemical on-site water analysis with simple, commercially available tests. Data will be uploaded by smartphone / internet and processed to provide public accessible near real time maps in internet. The incorporation of the citizens through schools and the public availability of the results can be an effective and sustainable way to improve the understanding of the water resource, its importance as well as the importance of the research conducted in the base project. E.g. spreading of pollutant plumes should be covered. The implementation of the specific citizen science component is done in close cooperation with the Mexican partner. In the base project Xibalba, a collaboration between European and Mexican partners, one essential approach is innovative stochastic generation of a hydrological model, which enables estmation of capacity, dynamics, and robustness of the ground water system. The additional TCS-project should extend the input data set to longer time series and extended spatial coverage (up to 22 months, 1 measurement per day, 30 locations) which would improve the model significantly.