# Automated Low Investment Cost Evaporometers (ALICEs)
## 1 Introduction  
The major components of the hydrological cycle are precipitation, evaporation, transpiration, infiltration, groundwater, and streamflow. Precipitation provides the input of water to watersheds, primarily as rain, snow, sleet, and hail. Precipitation moving in macro-pores and mesopores that are well connected vertically through the entire soil mantle is the primary mechanism for the resupply of groundwater, known as groundwater recharge [1]. Evaporation is the movement of water from the liquid state to the vapor state and then to the atmosphere. Evaporation occurs from any wet surface. The process effectively reduces the moisture in the soil on leaves that have been moistened by rain, or the moisture in the water body itself. Transpiration, another major evaporative process, is water that moves from the soil and roots via the plant's internal moisture supply system to the atmosphere. Transpiration moves through the stomates, which are minute openings in the leaves, mostly on their undersides, that allow the passage of oxygen, carbon dioxide, water vapor, and other gases. The combined evaporative processes are termed evapotranspiration [2]. Streamflow is the combined result of all climatological and geographical factors that operate in a watershed. It is the only phase of the hydrological cycle in which the water is confined in well-defined channels, and this permits accurate measurements to be made of the involved quantities. Other measurements of the hydrological cycle are point measurements for which the uncertainties, on an area basis, are difficult or impossible to estimate [3]. Point precipitation is measured using a gauge, which consists of a collector to delineate the area of the sample and a funnel leading to a storage device. The area ofthe collector and the size of the gauges vary depending on the amount of precipitation normally received in the region where the station is located [4]. Several methods are available for estimating the evaporation from an open water body. These have significant drawbacks, mainly the requirement for several meteorological variables, for example: wind velocity and humidity measurements. These values are not commonly available in most watersheds [5]. The evaporation pan method is generally considered the least accurate method. It is the only existing method that does not require site-specific measurements and that is commonly used in water resource investigations [6]. The pan, which is a routine evaporometer at hydrological and meteorological stations, is the simplest, cheapest, and most practical meteorological method for measuring local atmospheric evaporation demand [7]. Additionally, pan evaporation measurements provide an important reference for water resource assessment, hydrological research, climatic zoning, and for monitoring evaporative climate change [7; 8; 9]. A basic tool for computing the water balance and for estimating water availability and requirements is the estimation of evapotranspiration from vegetated surfaces. Research in this area is abundant, and it has provided theoretical knowledge and practical applications, mainly validated through adequate field measurements [10]. In addition to evapotranspiration, evaporation from the water surface is one of the determining components of the hydrological water cycle. Evaporometers are used to measure it. The simplest evaporometer is an evaporometer from the free water surface. The evaporation rate is calculated by the change in the level of the free water surface [11]. The determining parameter of the evaporator is the accuracy with which it measures the change in water level, and thus the water loss in mm. The evaporation is most often measured in mm per day. In addition to operational shortcomings, the problem with professional evaporometers is the high price, which limits the scale of their use, and thus the spatial accuracy of the measurements [12]. The most widely used method for measuring the water level in an evaporometer is currently a float connected via a pulley to a counterweight.