In the management of the water cycle, hydraulic engineering ensures an appropriate supply in quantity and quality at each stage of the cycle. This translates, in a first stage, into continuously providing drinking water, and in later stages, into ensuring that the water is properly treated. Hydraulic engineering can be divided into other subsets: structural hydraulic engineering, water treatment (prior to consumptionː purification) and wastewater treatment (after water consumptionː purification). Structural hydraulic engineering involves the construction, repair and maintenance of structures that control water resources. Regarding the management of the water cycle, the most important are reservoirs, dams, sewers, water treatment plants, desalination plants where appropriate, treatment plants and pumping stations.

In terms of water cycle management, reuse treatments are more important than static structures such as dams. Water treatment is any process used to remove contaminants from water and improve its quality. The treatment method depends on the use that is going to be given to that water. With the appropriate treatments it is possible, on an ascending scale of complication and price.

The objective of wastewater treatment is to clean it of contaminants and adapt it to the next step in its cycle (usually, dumping it into nature, but it can be something else, as just said).

Wastewater is treated with various physical, chemical, biological (using bacteria) and ultraviolet (UV) disinfection methods.[7]​ Still, after extensive treatment methods, significant amounts of harmful substances, such as pharmaceutical compounds, are observed to return to the environment and the water cycle.[8]​.

The growing population requires managing the hydrosphere in a sustainable way. There is a demand for fresh water that needs to be met, now and in the future. An important factor in this growing demand is climate change, which, by increasing droughts and episodes of torrential rains, reduces the availability of water. With water saving policies (water efficiency), countries can ensure water availability for future generations, reduce energy use, conserve freshwater habitat for local wildlife and migratory birds, and ensure water quality for their inhabitants.[9]​.

The key activities to save water are 2ː.

a) Reduce losses (leaks) in the supply network, which can reach 30% in old networks, but can be reduced to less than 1% with new pipes that are adequately monitored and maintained.[10]​.

b) Use water optimally, avoiding waste (for example, drip irrigation at night - there is less evaporation - instead of blanket irrigation at midday).[11]​.

To ensure successful water cycle management, environmental monitoring (sensors that capture the flow of natural watercourses, the level of underground aquifers, the filling of reservoirs, etc.) should be used to collect information and calculate the effects of possible decisions on ecosystems;[12]​ for example, monitoring the effects of reducing water flows on salmon spawning.

In Spanish, the RAE admits the verbs monitorear[13]​ and monitorizar,[14]​ with the same meaning (to observe, using special devices, the course of one or more physiological or other parameters to detect possible anomalies), from which respectively the nouns monitoreo and monitorización, also present[15]​[16]​ in the Academy's dictionary, are derived.

In the management of the water cycle, hydraulic engineering ensures an appropriate supply in quantity and quality at each stage of the cycle. This translates, in a first stage, into continuously providing drinking water, and in later stages, into ensuring that the water is properly treated. Hydraulic engineering can be divided into other subsets: structural hydraulic engineering, water treatment (prior to consumptionː purification) and wastewater treatment (after water consumptionː purification). Structural hydraulic engineering involves the construction, repair and maintenance of structures that control water resources. Regarding the management of the water cycle, the most important are reservoirs, dams, sewers, water treatment plants, desalination plants where appropriate, treatment plants and pumping stations.

In terms of water cycle management, reuse treatments are more important than static structures such as dams. Water treatment is any process used to remove contaminants from water and improve its quality. The treatment method depends on the use that is going to be given to that water. With the appropriate treatments it is possible, on an ascending scale of complication and price.

The objective of wastewater treatment is to clean it of contaminants and adapt it to the next step in its cycle (usually, dumping it into nature, but it can be something else, as just said).

Wastewater is treated with various physical, chemical, biological (using bacteria) and ultraviolet (UV) disinfection methods.[7]​ Still, after extensive treatment methods, significant amounts of harmful substances, such as pharmaceutical compounds, are observed to return to the environment and the water cycle.[8]​.

The growing population requires managing the hydrosphere in a sustainable way. There is a demand for fresh water that needs to be met, now and in the future. An important factor in this growing demand is climate change, which, by increasing droughts and episodes of torrential rains, reduces the availability of water. With water saving policies (water efficiency), countries can ensure water availability for future generations, reduce energy use, conserve freshwater habitat for local wildlife and migratory birds, and ensure water quality for their inhabitants.[9]​.

The key activities to save water are 2ː.

a) Reduce losses (leaks) in the supply network, which can reach 30% in old networks, but can be reduced to less than 1% with new pipes that are adequately monitored and maintained.[10]​.

b) Use water optimally, avoiding waste (for example, drip irrigation at night - there is less evaporation - instead of blanket irrigation at midday).[11]​.

To ensure successful water cycle management, environmental monitoring (sensors that capture the flow of natural watercourses, the level of underground aquifers, the filling of reservoirs, etc.) should be used to collect information and calculate the effects of possible decisions on ecosystems;[12]​ for example, monitoring the effects of reducing water flows on salmon spawning.

In Spanish, the RAE admits the verbs monitorear[13]​ and monitorizar,[14]​ with the same meaning (to observe, using special devices, the course of one or more physiological or other parameters to detect possible anomalies), from which respectively the nouns monitoreo and monitorización, also present[15]​[16]​ in the Academy's dictionary, are derived.