Detail of GB/T 50027-2024

Introduction of GB/T 50027-2024

GB/T 50027-2024 Standard for hydrogeological investigation of water-supply 1 General provisions 1.0.1 This standard is formulated to standardize the hydrogeological investigation of water-supply, correctly reflect hydrogeological condition, reasonably evaluate, develop and protect groundwater resources, ensure the water supply security and maintain the ecological environment. 1.0.2 This standard is applicable to hydrogeological investigations using groundwater as the water supply source. 1.0.3 In addition to this standard, the hydrogeological investigation of water-supply shall also meet the requirements of the current relevant standards of China. 2 Terms and symbols 2.1 Terms 2.1.1 hydrogeological investigation of water-supply hydrogeological investigation work conducted for the purpose of water supply. 2.1.2 hydrogeological condition general term for the burial, distribution, recharge, runoff and discharge of groundwater, water quantity and quality, and the geological conditions for its formation 2.1.3 hydrogeological unit groundwater system with uniform boundaries and recharge, runoff, drainage conditions 2.1.4 hydrogeological parameters general term for indicators characterizing hydrogeological characteristics of strata, including the permeability coefficient, water release coefficient, water supply degree, precipitation infiltration coefficient, phreatic evaporation coefficient, and overflow parameters 2.1.5 groundwater regime state of elements of groundwater, such as the water level, water quantity, water temperature, and chemical composition, over time under the comprehensive influence of various factors 2.1.6 hydrogeological exploration borehole borehole constructed according to the requirements of hydrogeological drilling to identify the hydrogeological conditions or parameters 2.1.7 steady-flow pumping test pumping test in which the groundwater flow field and various elements can reach a new stable state in the process of pumping 2.1.8 unsteady-flow pumping test pumping test in which the groundwater flow field and various elements cannot reach a new stable state in the process of pumping 2.1.9 single well pumping test pumping test in which water is pumped from only one pumping well and no observation well is configured 2.1.10 single well pumping test with observation wells pumping test in which water is pumped from one pumping well and observation wells are configured 2.1.11 pumping test of well group pumping test in which water is pumped from two or more pumping wells at the same time, observation wells are configured, and the water level and water quantity of each well have obvious mutual influence 2.1.12 trail-exploitation pumping test pumping test as required under trail-exploitation conditions or a condition close to such conditions 2.1.13 separate-interval pumping test pumping test in which pumping and observation are carried out respectively while the target aquifer of the pumping test is isolated from other aquifers 2.1.14 groundwater recharge volume of water entering an aquifer per unit of time under natural or exploitation conditions 2.1.15 groundwater storage volume of gravitational water residing in an aquifer 2.1.16 groundwater discharge volume of water discharged from an aquifer per unit time under natural or exploitation conditions 2.1.17 groundwater resource evaluation evaluation to demonstrate, under certain economic and technical exploitation conditions, exploitable reserves, under which the water level does not drop beyond the allowable range, the volume of exploitable water does not decrease, the water quality does not deteriorate, the water temperature complies with the standards, and no environmental geological problems exist, or environmental risks caused are acceptable 2.1.18 evaluation of groundwater quantity comprehensive evaluation of the recharge, discharge, storage and exploitable reserves of groundwater sources or a certain area or aquifer, as well as the suitability of calculation methods used, reliability of hydrogeological parameters, accuracy of resource calculation results, and resource exploitation guarantee degree 2.1.19 exploitable reserves of groundwater maximum volume of water that can be exploited from the hydrogeological unit or water intake section per unit time, through investigation or exploitation verification, during the whole exploitation period provided that the change of groundwater quality meets the utilization requirements, the groundwater level does not continue to decline, and no harmful ecological and environmental geological phenomena occur 2.1.20 allowable withdrawal of groundwater volume of water allowed to be exploited from the hydrogeological unit or water intake section per unit time, through investigation or exploitation verification, under the current economic, technical, ecological and environmental conditions and when the requirements for groundwater resource management and control are met 2.1.21 conceptual hydrogeological model simplified model that is convenient for mathematical and physical simulation and formed by generalizing the actual boundary type, internal structure, permeability properties, hydraulic characteristics and conditions of recharge and excretion of aquifers with language or graphics 2.1.22 numerical model of groundwater a set of mathematical relations that are established based on the conceptual hydrogeological model, and close to the actual groundwater system structure, water flow movement characteristics and various infiltration elements 2.1.23 calibration of numerical model calculation process used to analyze the calculation results of the numerical model of groundwater according to the known initial and boundary conditions to select reasonable parameters (i.e. parameter calibration) and correct the established numerical model 2.1.24 verification of numerical model process during which the data different from the calculation period used for model calibration are selected for numerical simulation using the model parameters after model calibration and initial and boundary conditions and the calculated data are compared with the actual observation data to test the simulability of the numerical model to select a reasonable mathematical model 2.1.25 groundwater forecast forecast of the changes in groundwater level and water quantity over time and space under given exploitation conditions based on the selected numerical model 2.1.26 radioactive tracer logging method to determine some hydrogeological parameters of aquifers by tracing or dilution principle using artificial radioisotopes, such as 131I and 82Br, to mark groundwater flow in natural flow fields or borehole in artificial flow fields 2.2 Symbols B —— the width of the calculated section, and the overflow parameter; C —— the phreatic evaporation coefficient; E —— the evaporation discharge of groundwater; F —— the aquifer area and precipitation infiltration area; h —— the pressure head height of the confined groundwater aquifer from the roof, the thickness of the phreatic aquifer in the pumping test, the water level height of the phreatic aquifer in the observation well before precipitation, and the thickness of the phreatic aquifer at the time of water level recovery; —— the average thickness of the phreatic aquifer under natural conditions and at the pumping test; △h² —— the square difference between the thickness, H, of the phreatic aquifer under natural conditions, and the thickness, h, during the pumping test; H —— the thickness of the phreatic aquifer under natural conditions; i —— the slope at the inflection point of the curve; I —— the hydraulic gradient of groundwater; K —— the permeability coefficient; L —— the length of the filter; L0 —— the inlet length of filter at phreatic aquifer under natural conditions; M —— the thickness of confined groundwater aquifer; N0 —— the initial count rate of isotopes; N b—— the radioactive background count rate; N t—— the count rate of isotopes at time t; P —— the precipitation; Q —— the water output, groundwater runoff, and precipitation infiltration recharge; r —— the radius of the pumping well filter, the distance from the observation well to the pumping well, and the inner radius of the filter; r0 —— the probe radius; rw —— the pumping well radius; R —— the radius of influence; S —— the water release coefficient of confined aquifer; s —— the water level drop value, the residual drop value when water level recovers, the water level drop depth; t—— the time; V —— the volume and flow velocity of phreatic aquifer; V f—— the infiltration velocity at the measuring point; W(u) —— the well function; W —— the storage and elastic storage of groundwater; △W —— the change in groundwater storage; α —— the precipitation infiltration coefficient, and flow field distortion correction coefficient; β —— the irrigation leakage recharge coefficient; ε —— the evaporation discharge of phreatic water; ε 0—— the evaporation discharge from water surface; μ —— the specific yield of phreatic aquifer.

Contents of GB/T 50027-2024

Contents 1 General provisions (1) 2 Terms and symbols (1) 2.1 Terms (1) 2.2 Symbols (4) 3 Basic requirements (7) 4 Hydrogeological mapping (11) 4.1 General requirements (11) 4.2 Basic requirements (14) 4.3 Special requirements (16) 5 Geophysical exploration for hydrogeological investigation (20) 5.1 General requirements (20) 5.2 Geophysical exploration arrangement and method selection (20) 6 Drilling and pore-forming (22) 6.1 General requirements (22) 6.2 Arrangement of exploration holes (22) 6.3 Structure of exploration holes (24) 6.4 Pumping well filter (24) 6.5 Construction of exploration holes (26) 6.6 Sampling of exploration holes (27) 7 Pumping test (29) 7.1 General requirements (29) 7.2 Steady-flow pumping test (31) 7.3 Unsteady-flow pumping test (32) 8 Groundwater regime observation (34) 8.1 General requirements (34) 8.2 Water level observation (34) 8.3 Water quantity observation (36) 8.4 Water quality observation (36) 8.5 Water temperature and air temperature observation (37) 9 Calculation of hydrogeological parameters (38) 9.1 General requirements (38) 9.2 Hydraulic conductivity (39) 9.3 Specific yield and storage coefficient (44) 9.4 Infiltration coefficient of precipitation (45) 9.5 Phreatic water evaporation coefficient (46) 9.6 Radius of influence (46) 10 Groundwater resource evaluation (48) 10.1 General requirements (48) 10.2 Evaluation of groundwater quantity (51) 10.3 Evaluation of groundwater quality (60) 11 Environment evaluation and protection of ground water resources (62) 11.1 General requirements (62) 11.2 Evaluation of ambient environment (62) 11.3 Evaluation of environment forecast (63) 11.4 Protection of groundwater resources (63) 12 Data archiving and file management (65) 12.1 General requirements (65) 12.2 Data archiving (65) 12.3 File management (66) Annex A Preparation of outline of hydrogeological investigation of water-supply (68) Annex B Common geophysical exploration methods of hydrogeological investigation (71) Annex C Common methods of groundwater evaluation and forecast (75) Explanation of wording in this standard (86) List of quoted standards (87) Addition: Explanation of provisions (89)