What Is Groundwater Hydrology?

Groundwater hydrology is a branch of hydrology that uses the principles of hydrological cycle and water balance to study groundwater formation, movement, water regime, and groundwater resources. It is closely related to hydrogeology, which mainly studies the origin, type, distribution, movement, chemical composition of groundwater, and geological environment, but the research content has its own emphasis. Groundwater is a water body in nature. Underground runoff is a link in the hydrological cycle. Groundwater resources are an important part of water resources. Therefore, the study of groundwater is not only of theoretical significance, but also of practical significance in solving the problems of water supply, drainage and soil salinization.

Chinese name: Groundwater hydrology
Foreign name: Groundwater hydrology

Subject: Geography
research content: Groundwater origin, type, distribution, movement

History of groundwater hydrology

The history of groundwater hydrology can be divided into three periods:

Groundwater Hydrology

From the 7th century BC to the 16th century BC, during the two thousand years, people were limited to direct observation and speculation of phenomena. Plato speculated that there was a huge cave underground, and the water in it was the source of the river. Liu Zongyuan (773 ~ 819) of the Tang Dynasty of China said in "Tian Du" that "the veins of the acupoint soil are turbid and clear. They are sparse, thirst and rise. There is more than enough, and the leakage is repeated." The existence of rock and soil voids, its infiltration, evaporation and flow.

Groundwater Hydrology Foundation

From the 17th century to the beginning of the 20th century, scientists have put forward a series of important concepts, laws and methods about groundwater formation and movement through observation, experimentation and analysis. French scientist P. Perot studied the capillary rise of groundwater and found that the capillary water rise in the sand was less than 1 meter. French scholar E. Mallet measured the amount of groundwater recharged by rainwater infiltration, and concluded that spring water is recharged by rainfall infiltration. In 1856, the French engineer H.-P.-G. Darcy established the basic law of groundwater seepage through experiments and laid the foundation for groundwater movement.

Hydrogeological survey Theoretical basis. In 1863, the French scholar J.-J. Choppy made some simplifications and assumptions based on the fact that the actual diving surface slope was small, and derived the groundwater flow formula using Darcy's law. In 1870, the German A. Tim improved the couture formula, so that the constant flow pumping test can be used to calculate parameters such as permeability coefficient. These work laid the foundation for the development of groundwater hydrology.

Groundwater Hydrology Development Period

From the beginning of the 20th century to the early 1980s, due to the needs of production and the advancement of science and technology, groundwater hydrology gradually formed an independent discipline and has developed rapidly. In 1928, American scholar OE Mainzell discussed the compressibility and elasticity of confined aquifers, and prepared a rich practical basis for the establishment of groundwater instability theory. In 1935, the American scholar CV Theis used the similarity between groundwater unsteady flow and heat conduction to derive the famous Theis formula. In 1937, the American scholar M. Muskett systematically discussed the motion of groundwater in the book "Flow of Uniform Fluid through Porous Media". In 1954, the British scholar NS Bolton derived the equation of unsteady flow for a submerged well. In 1930, Dutch hydro engineer GJ De Hele used mathematical methods to analyze the phenomenon of groundwater seepage through weak permeable layers. Research on groundwater pollution has been developed since the 1960s. After 1949, China has done a lot of work on the evaluation of groundwater resources, the prediction of groundwater levels and exploitation, the determination of hydrological and hydrogeological parameters and the calculation of groundwater regulation in a large area, and achieved results.

Groundwater hydrology research content

The research content of groundwater hydrology can be summarized as:

Formation of groundwater

Groundwater mainly comes from infiltration of atmospheric precipitation and surface water, and infiltration of irrigation water in irrigation areas. Infiltrated

Groundwater hydrological information simulation map Water is redistributed underground (storage, evaporation, and horizontal excretion) to form part of the natural hydrological cycle. Groundwater hydrology studies the role of groundwater in the natural water cycle, studies its connections and transformations with precipitation, evaporation, surface water, its recharge, excretion, and related hydrological and hydrogeological parameters (such as precipitation infiltration and recharge coefficients) , Water supply, etc.) and groundwater resource evaluation.

Groundwater hydrology groundwater movement

Groundwater produces seepage motion under the action of gravity and pressure. The basic law of groundwater movement is Darcy's law. The mathematical and physical equations of groundwater movement under different conditions can be derived based on the principle of conservation of mass and Darcy's law. The basic method for calculating groundwater motion is to find solutions to these equations under various initial and boundary conditions. The solution of the equation of groundwater movement can be used to predict hydrological factors such as groundwater level at a certain place in the future, and hydrogeological parameters such as hydraulic conductivity can be calculated, providing a reliable basis for groundwater resource evaluation.

Groundwater hydrology

Also known as groundwater dynamics, refers to changes in groundwater level, water quantity, water quality, and water temperature under the influence of natural and human factors. Study these changes and establish a quantitative relationship between the elements in time and space. Observation stations and test sites are usually used to conduct groundwater observations and field tests, use the obtained data to calculate hydrological and hydrogeological parameters, evaluate the amount of groundwater recharge, storage and allowable exploitation, and monitor the quality of groundwater to prevent groundwater pollution .

Groundwater Hydrology Development and Management

Groundwater development should be planned and rationalized based on the identification of groundwater resources. In addition to drawing up plans for groundwater management, a groundwater management agency must be established; reasonable allocation of water resources; technical requirements for groundwater extraction; protection of water sources to prevent pollution; prevention of ground subsidence or subsidence caused by pumping water, and intrusion of seawater; Ensure long-term safe water supply. Groundwater hydrology also includes: aerated zones, soil water, diving, confined water, aquifers, springs, groundwater movement (Darcy's law, water permeability coefficient, water permeability coefficient, water supply, water release coefficient, precipitation infiltration and recharge Coefficient, irrigation water infiltration and recharge coefficient), groundwater forecast, groundwater calculation (groundwater simulation), groundwater development and utilization, groundwater management, etc.

Research methods of groundwater hydrology

Groundwater Hydrology Research Approach

Mathematical physics approach. Based on the physical relationship between groundwater regime and influencing factors, establish a quantitative relationship between them. For example, the water balance method is used to find the quantitative relationship between various balanced elements, and the ground is solved according to certain initial conditions and boundary conditions.

Classification of groundwater quality categories Mathematical and physical equations of launching motion.

Statistical approach. Based on a large number of measured data, the statistical laws of various hydrological elements of groundwater are studied using the principle of probability statistics, and groundwater prediction and groundwater calculation are performed.

Groundwater Hydrology Research Methods

Drilling, geophysical exploration and remote sensing technology. It is mainly used to ascertain burial conditions, spatial distribution and aquifer properties.

Test and observation. Including pumping test, groundwater dynamic observation and soil water observation of well spring.

Groundwater simulation technology. For example, in electrical simulation, a network of resistors and capacitors is used to simulate regional groundwater flow systems.

Isotope technology. Used to study soil water content, origin of groundwater, age and movement (see Hydrological and Nuclear Technology).

Groundwater Hydrology Discipline Relationship

The formation and distribution of groundwater are closely related to the geology and geographical environment. Therefore, groundwater hydrology is related to geology and geography. The research of groundwater movement should be based on the basic theory of hydraulics and fluid mechanics. Probability theory and mathematical statistics are widely used in the analysis of groundwater dynamic data and groundwater prediction. Because groundwater hydrology studies groundwater from the perspective of hydrological cycle, it is closely related to climatology, surface hydrology, and soil science. Evaluation of groundwater quality using hydrochemistry and hydrogeology

Groundwater use classification diagram Learn knowledge. In addition, systematic analysis theory has been gradually adopted in the development and utilization of groundwater.

There are some problems in groundwater hydrology, such as the conversion relationship between precipitation, surface water and groundwater. There are few studies on groundwater resources and their optimal development and management. Under complex hydrogeological conditions in large areas, there is no perfect way to determine aquifer parameters. Carrying out indoor and outdoor observation and experimental research on water balance factors, establishing new mathematical and physical models, and applying electronic computers and electrical simulation techniques may make progress in the above issues. In addition, more research is expected in the fields of dispersion of pollutants, temperature fields in aquifers, and dynamic laws and prediction of groundwater.