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
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)
供水水文地质勘察标准
1 总则
1.0.1 为规范供水水文地质勘察，正确地反映水文地质条件，合理地评价、开发和保护地下水资源，保障供水安全，维持生态环境，制定本标准。
1.0.2 本标准适用于以地下水作为供水水源的水文地质勘察。
1.0.3 供水水文地质勘察，除应符合本标准外，尚应符合国家现行有关标准的规定。
2 术语和符号
2.1 术语
2.1.1 供水水文地质勘察 hydrogeological investigation of water-supply
以供水为目的而进行的水文地质勘察工作。
2.1.2 水文地质条件 hydrogeological condition
地下水的埋藏、分布、补给、径流和排泄，水量和水质及其形成 的地质条件等的总称。
2.1.3 水文地质单元 hydrogeological unit
具有统一边界和补给、径流、排泄条件的地下水系统。
2.1.4 水文地质参数 hydrogeological parameters
表征地层水文地质特征指标的统称，包括渗透系数、释水系 数、给水度、降水入渗系数、潜水蒸发系数、越流参数等。
2.1.5 地下水动态 groundwater regime
在各种因素综合影响下，地下水的水位、水量、水温及化学成分等要素随时间的变化状态。
2.1.6 水文地质勘探孔 hydrogeological exploration borehole
为查明水文地质条件或参数，按水文地质钻探要求施工的钻孔。
2.1.7 稳定流抽水试验 steady-flow pumping test
在抽水过程中地下水流场及各要素能够达到一种新的稳定状态的抽水试验。
2.1.8 非稳定流抽水试验 unsteady-flow pumping test
在抽水过程中地下水流场及各要素不能够达到新的稳定状态的抽水试验。
2.1.9 单孔抽水试验 single well pumping test
只在一个抽水孔中进行的不带观测孔的抽水试验。
2.1.10 多孔抽水试验 single well pumping test with observation wells
在一个抽水孔中抽水并带观测孔的抽水试验。
2.1.11 群孔抽水试验 pumping test of well group
在两个或两个以上的抽水孔中同时抽水并配置观测孔，各孔的水位和水量有明显相互影响的抽水试验。
2.1.12 开采性抽水试验 trail-exploitation pumping test
按开采条件或接近开采条件要求进行的抽水试验。
2.1.13 分层抽水试验 separate-interval pumping test
将抽水试验的目标含水层与其他含水层隔离，分别进行抽水及观测的抽水试验。
2.1.14 地下水补给量 groundwater recharge
在天然或开采条件下，单位时间内进入含水层的水量。
2.1.15 地下水储存量 groundwater storage
赋存于含水层中的重力水体积。
2.1.16 地下水排泄量 groundwater discharge
在天然或开采条件下，单位时间内从含水层中排出的水量。
2.1.17 地下水资源评价 groundwater resource evaluation
在一定的经济技术开采条件下，论证水位下降不超过允许范围、可开采水量不发生减少、水质不发生恶化、水温符合标准、不产生环境地质问题或产生的环境风险是可接受条件下的可开采量。
2.1.18 地下水资源量评价 evaluation of groundwater quantity
对地下水水源地或某一地区、某个含水层的补给量、排泄量、储存量、可开采量以及对所用计算方法的适宜性、水文地质参数的可靠性、资源计算结果精度、资源开采保证程度所做出的全面评价。
2.1.19 地下水可开采量 exploitable reserves of groundwater
经勘察或开采验证，在整个开采期内，地下水水质变化符合利用要求，地下水水位不发生持续下降，不发生危害性的生态、环境地质现象的前提下，单位时间内从水文地质单元或取水地段中能够开采出来的最大水量。
2.1.20 地下水允许开采量 allowable withdrawal of groundwater
经勘察或开采验证，在当前经济、技术、生态、环境允许条件下并满足地下水资源管控要求时，允许单位时间内从水文地质单元或取水地段中开采出来的水量。
2.1.21 水文地质概念模型 conceptual hydrogeological model
用语言或图示将含水层实际的边界类型、内部结构、渗透性质、水力特征和补给、排泄等条件概化后所形成的便于进行数学与物理模拟的简化模型。
2.1.22 地下水数值模型 numerical model of groundwater
以水文地质概念模型为基础所建立的，能接近实际地下水系统结构、水流运动特征和各种渗透要素的一组数学关系式。
2.1.23 数值模型识别 calibration of numerical model
根据已知的初始、边界条件，对地下水数值模型的计算结果进行分析，以达到选择合理参数(即参数识别)，校正已建数值模型的计算过程。
2.1.24 数值模型检验 verification of numerical model
采用经模型识别后的模型参数和初始、边界条件，选用不同于模型识别所用计算时段的资料进行数值模拟，将计算所得数据和实际观测数据进行对比，检验数值模型的仿真性，从而选定合理数学模型的过程。
2.1.25 地下水预报 groundwater forecast
在采用选定的数值模型基础上，在给定开采条件下，预报地下水的水位、水量在时间和空间上的变化。
2.1.26 同位素示踪测井 radioactive tracer logging
采用人工放射性同位素131I，82Br等标记天然流场或人工流场中钻孔内的地下水流，利用示踪或稀释原理测定含水层某些水文地质参数的方法。
2.2 符号
B —— 计算断面的宽度、越流参数；
C —— 潜水蒸发系数；
E —— 地下水的蒸发量；
F —— 含水层的面积、降水入渗面积；
h —— 承压水含水层自顶板算起的压力水头高度、潜水含水层在抽水试验时的厚度、潜水含水层在降水前观测孔中的水位高度、水位恢复时的潜水含水层的厚度；
—— 潜水含水层在自然情况下和抽水试验时的厚度平均值；
△h² —— 潜水含水层在自然情况下的厚度H和抽水试验时的厚度h的平方差；
H —— 天然情况下潜水含水层的厚度；
i —— 曲线拐点处的斜率；
I —— 地下水水力坡度；
K —— 渗透系数：
L —— 过滤器的长度；
L0 —— 天然情况下潜水含水层过滤器进水长度；
M —— 承压水含水层的厚度；
N0 —— 同位素初始计数率；
N b—— 放射性本底计数率；
N t—— 同位素t时计数率；
P —— 降水量；
Q —— 出水量、地下水径流量、降水入渗补给量；
r —— 抽水孔过滤器的半径、观测孔至抽水孔的距离、过滤器内半径；
r0 —— 探头半径；
rw —— 抽水孔半径；
R —— 影响半径；
S —— 承压含水层释水系数；
s —— 水位下降值、水位恢复时的剩余下降值、水位降深；
t—— 时间；
V —— 潜水含水层的体积、水流速度；
V f—— 测点的渗透速度；
W(u) —— 井函数；
W —— 地下水的储存量、弹性储存量；
△W —— 地下水储存量的变化量；
α —— 降水入渗系数、流场畸变校正系数；
β —— 灌溉渗漏补给系数；
ε —— 潜水蒸发量；
ε 0—— 水面蒸发量；
μ —— 潜水含水层给水度。
