Into the Depths: Exploring Mar Menor’s Virtual Counterpart

In 2019, a massive fish kill was reported from the iconic Mar Menor – likely a result of prolonged water column stratification and a long period of hypoxia (low oxygen levels) in large parts of the lagoon. Stratification, where the water column “divide” into distinct layers of density due to different temperatures or salinity, can oftentimes result in low or even completely depleted oxygen levels near the bottom. Even if these stratification events are short-lived (e.g. a few days or less), as is typical in shallow systems, such as Mar Menor, this can still be enough to cause low oxygen levels near the bottom. Oxygen dynamics is a key indicator of water quality and ecosystem health, as this has direct influence on the habitable area for aquatic life, which can suddenly shrink during these stratification events.

In the SMARTLAGOON project we are building a digital twin of the lagoon and its entire watershed. The twin, which integrates state-of-the-art water quality models and real-time sensor data, is intended to give real-time insights into the life of the lagoon, and also forecast the risk of hypoxia in the short-term future. The models of the digital twin are made operational through the ASAP Portal developed by WaterITech and WaterWebTools. ASAP is a cloud-based multi-source integration platform that overlays with modeling, real-time IoT data capture, and weather data, and makes advanced forecasting and analysis easy. River discharges, lagoon temperature and oxygen levels, and more, can thereby be forecasted 9 days into the future, giving insights into the risk of upcoming flooding, drought or water quality challenges, and thereby potentially providing decision support for water authorities and emergency responses.

The ASAP Portal currently integrates the SWAT+ catchment hydrology and nutrient export model, the GOTM-WET hydrodynamic-ecosystem model, and real-time sensor data from the SMARTLAGOON buoy installed in the deepest point of Mar Menor. A couple of key innovations developed by WaterITech in SMARTLAGOON include the ability to run a fully dynamic coupling of the catchment and lagoon dynamics, whereby forecasted catchment runoff is used in the lagoon forecast, and also the ability to acquire real-time sensor data from the buoy in Mar Menor, and assimilate the sensor data into the model forecasts by a hotstart functionality, thereby potentially improving forecast skill. The models used in the digital twin will undergo further improvements throughout the SMARTLAGOON project, and the digital twin and its forecasts will therefore also undergo incremental improvements. A prototype version of the digital twin of Mar Menor in the ASAP Portal, was recently made openly available for all to view and test.

Here is a direct link to Mar Menor project in the ASAP Platform: https://asap-forecast.com/public?lat=37.72348507722568&lon=-0.7920903503149291&zoom=10&projects=a1c02d60-7d35-11ed-a545-0242ac1c0003,5364acce-8bb3-11eb-abb3-0242ac120007,81157036-8bb3-11eb-9858-0242ac120007.

Below are some examples of outputs from the three key elements of the digital twin (catchment and lagoon models, and realtime sensor-system, respectively).

 

Example of catchment model output from the ASAP Portal. Key water balance components (e.g. river discharge, surface runoff, groundwater recharge etc.) for different parts of the landscape can easily be visualized.

 

Example of lagoon model output from the ASAP Portal. In this example, the oxygen levels near the bottom of the lagoon are transposed onto a bathymetric map the lagoon – giving an indication of the extent of the areas that are experiencing low oxygen levels within a forecast time window.

 

Example of real-time data from the sensors of the buoy in Mar Menor. The sensor system currently includes temperature and oxygen levels at different depths, salinity, chlorophyll a (a proxy for algal levels) and turbidity. Data is transmitted to the cloud and integrated into the ASAP Portal at approx. 10-15 min intervals.