1.0.1 This Standard is formulated with view to carrying out hydrogeological investigation works better, correctly reflecting hydrogeological conditions, reasonably evaluating, developing and protecting groundwater resources and maintaining good ecological environment.
1.0.2 This Standard is applicable to hydrogeological investigation for water supply of cities, towns and industrial and exploitation enterprises.
1.0.3 The investigation tasks and requirements must be made clear, the existing data must be collected and analyzed, the site exploration must be carried out and the investigation program must be proposed before carrying out the hydrogeological investigation of water supply. The report on hydrogeological investigation of water supply shall be prepared after completing hydrogeological investigation works.
1.0.4 The work details and amount of hydrogeological investigation of water supply shall be determined according to factors such as: hydrogeological condition complexity, water demand scale, different investigation phases, works completed, planned methods of groundwater resource evaluation, etc.
1.0.5 The complexity of hydrogeological conditions may be divided as simple, medium, and complex categories. The division principles should conform to the requirements specified in Table 1.0.5.
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.0.6 By water demand, proposed water supply sources may be divided into:
Extra-large scale: Water demand ≥ 15×104 m3/d
Large scale: 5×104 m3/d ≤ water demand < 15×104 m3/d
Medium scale: 1×104 m3/d ≤ water demand ≤ 5×104 m3/d
Small scale: Water demand < 1×104 m3/d
1.0.7 Works of hydrogeological investigation of water supply are divided into four phases: groundwater prospecting, general exploration, exploration and exploitation. The results of works in different investigation phase shall satisfy the requirements in corresponding design phase.
Note: groundwater investigation works may be carried out as required where the local hydrogeological survey is not enough and the related data is lack.
1.0.8 Tasks and depth of hydrogeological investigation of water supply in all phases shall meet the following requirements:
1 Prospecting phase: evaluating the hydrogeological conditions of the area or the water demand region in summary; and proposing and preparing the data on whether the design groundwater amount can be met. The inferred exploitable groundwater on possible water-affluent section satisfies the Level D accuracy requirement, which provides the basis for preliminary design of town planning, general design of construction project or plant/facility location.
2 General exploration phase: basically ascertaining the hydrogeological conditions on several possible water-affluent sections; preliminarily evaluating groundwater resources, and carrying out the scheme comparisons on water sources. The indicated exploitable groundwater shall satisfy Level 3 accuracy requirement, which provides the basis for the preliminary design of the water source.
3 Exploration phase: ascertaining the hydrogeological conditions of and within the proposed water source; further evaluating groundwater resources; and proposing the rational exploitation plan. The measured exploitable groundwater shall satisfy Level 3 accuracy requirement, which provides the basis for the working drawing design of the water source.
4 Exploitation phase: ascertaining the possibility of exploitation extension of the water source, and analyzing the reasons of water amount decrease, water quality deterioration, adverse environment, engineering geology phenomenon and others. On the base of exploitation performance or special testing/study, the measured exploitable groundwater shall satisfy Level A accuracy requirement, which provides the basis for rational exploitation and preservation of groundwater resources, as well as re-building and extension of water source.
1.0.9 The investigation phase shall consistent with the design phases, and they may be simplified and combined according to actual conditions such as water demand, existing data and hydrogeological conditions. The allowable yield proposed after investigation phase simplification and combination shall satisfy the accuracy requirements of the high-level phase.
