Costs and benefits of automated high-frequency monitoring (AHFM) and modelling

The following pages present the costs and benefits of using automated high frequency monitoring (AHFM) in combination with dynamic modelling to obtain information for lake management.

Costs of AHFM

If you plan to shift from a standard lake monitoring programme to automated high frequency monitoring (AHFM) combined with dynamic modelling, you might wonder what it will cost. There is no simple answer, as there are various levels of technological options available which require different amounts of investment. For example, you might use single sensors to measure single parameters or you might install multi-probe sondes measuring several water quality parameters at a time; basic data and equipment are needed for measuring standard parameters, such as for weather; the instruments need time for installation and maintenance; and, the lake model has to be set up.

The links below lead to more detailed information about the costs of installing AHFM systems and setting up a dynamic lake modelling tool.

Guidelines for the development and installation of automated monitoring stations are available here.

NB! Equipment suppliers, mentioned in these pages, are only examples. The list is neither intended to be complete nor intended to promote specific suppliers.

Single Sensors

Information about the costs and suppliers for different types of single sensors.

Multi-probe sondes

Information about the costs and suppliers for typical multi-probe sondes.

Basic Equipment

Information about the costs for basic equipment. Sensors and sondes need to be mounted to buoys or land-based installations. Lake models need weather information to be able to predict future processes.

Installation and Maintenance

Information about installation and maintenance costs for monitoring equipment. Even though automatic, sensors require maintenance, such as refilling of chemicals or cleaning. In harsh weather conditions, e.g. ice on the lake, the monitoring system needs to be removed from the water to avoid damage.

Modelling

There are different types of models, which can be used to predict changes in lake water quality in lakes. The more complex a model is, the more time it will take to set it up. This link provides information about the costs of setting up a 1D model.

Benefits of AHFM

Automated high frequency monitoring (AHFM) cannot prevent detrimental changes to lake water quality, but it can help to detect changes that might have otherwise remained unobserved or been observed later. The combination of AHFM and modelling allows the state of the lake to be predicted, with a degree of uncertainty, in the near future. AHFM and modelling extends the time water managers have to respond to adverse changes in water quality. Using AHFM with or without modelling is, in fact, a “time gain”.

The time gain from employing AHFM must be compared with current monitoring intervals and, in case of episodic changes in water quality, also in relation to the length of these episodes. Assume, for example, that a water work, which takes in water directly from a nearby lake, takes weekly samples and analyses the concentration of cyanobacteria as an indicator of algae blooms. In case of a high concentration of cyanobacteria they will initiate additional treatment steps. When an algal bloom lasts 10 days and breaks out right after the water sample was taken, there may be up to 7 days before it is detected, i.e. 7 days of potentially harmful impacts. If AHFM is employed there will be up to 7 days time gain if the information is made directly available. If the duration of a harmful algal bloom is only 3 days, weekly sampling may not detect the bloom at all, but then the time gain by applying AHFM is only 3 days, i.e. equal to the duration of the bloom. The figure below illustrates this.

The PROGNOS project mainly focuses on two adverse changes in water quality: algal blooms and elevated concentrations of DOM. There might be other benefits of employing AHFM.