SL 77-1994 Specification for hydrological calculations for small hydroelectric power stations SL 77-94
Some standard content:
Industry Standard of the People's Republic of China
Hydrological Calculation Norms for Small HydropowerbzxZ.net
SL77—94
Editor: Rural Electrification Research Institute of the Ministry of Water ResourcesApproval Department: Ministry of Water Resources of the People's Republic of ChinaEffective Date: May 1, 1994
SL77-94
Ministry of Water Resources of the People's Republic of China
Notice on the Issuance of "Hydrological Calculation Norms for Small Hydropower Stations" (SL77-94)
Shui Ke Jiao [1994] No. 120
"Hydrological Calculation Norms for Small Hydropower Stations", edited by the Rural Electrification Research Institute of the Ministry of Water Resources, has been reviewed and approved as a water conservancy industry standard with the number SL77-94. This standard will be implemented from May 1, 1994. If you find any problems during implementation, please report them to the editorial department in a timely manner; the Ministry of Water Resources’ Hydropower and Rural Electrification Department is responsible for interpreting this specification, and it will be published and distributed by the Water Resources and Electric Power Press. April 5, 1994
Design runoff
Flow duration curve
Low flow analysis
Design flood
Water level-flow relationship
Sediment, evaporation, ice conditions and others
Reasonableness check of results
Rural Hydropower and Electrification Volume: Planning
Appendix A Additional notes on hydrological analysis and calculation of small hydropower stations with installed capacity less than 500kW and less than 100kW·
Article notes·
SL77--94
1 General provisions
1.0.1 This specification is formulated in combination with the characteristics of small hydropower to ensure the quality of hydrological analysis and calculation of small hydropower stations (hereinafter referred to as "small hydropower" or "small hydropower stations") and improve the reliability of the results. 1.0.2 This specification is applicable to the hydrological analysis and calculation of various small hydropower stations with installed capacity below 25,000 kW (including 25,000 kW) in the feasibility study and preliminary design stages, and should also be used as a reference in the planning stage. For power stations with installed capacity less than 500 kW, the content can be appropriately simplified and the requirements can be relaxed according to actual conditions; for micro power stations with installed capacity less than 100 kW, it can be implemented as a reference. See Appendix A for details.
1.0.3 The basic data for hydrological analysis and calculation of small hydropower stations should include the following: (1) hydrological and meteorological data;
(2) natural geography of the basin and river characteristics; (3) data on the impact of human activities such as the development of water conservancy and hydropower projects in the city; (4) comprehensive analysis and research results of hydrological and meteorological regions; (5) other relevant data.
1.0.4 Small hydropower hydrological analysis and calculation must be based on careful investigation and collection of basic data such as hydrology and meteorology, and according to data conditions and project characteristics, correctly apply my country's current small and medium-sized river basin hydrological analysis and calculation methods and regional comprehensive analysis and research results approved by administrative departments at or above the provincial level and their supporting query and calculation charts. 1.0.5 Small hydrological analysis and calculation reports should be compiled chapter by chapter in accordance with the contents of this specification, and the river basin conditions, reference stations, reference data, calculation methods and parameter quantification should be explained in sequence, and the analysis and calculation conclusions should be clearly given, and all adopted results and main charts should be listed in sequence.
1.0.6 If any of the indicators of installed capacity, storage capacity, and catchment area of small hydropower stations reaches the lower limit of the level of large and medium-sized water conservancy and hydropower projects, the hydrological analysis and calculation shall be carried out in accordance with the "Hydrological Calculation Specification for Water Conservancy and Hydropower Projects" (SDJ214-83) and "Design Flood Calculation Specification for Water Conservancy and Hydropower Projects" (SL4493). 2 Design runoff
2.0.1 For hydrological analysis and calculation of small hydropower stations, all or part of the following basic design runoff results should be provided: (1) Annual runoff, flood season runoff, dry season runoff, and driest month runoff of multi-year average and designated rate or each design representative year;
(2) Annual distribution of each design representative year. 2.0.2 For design runoff, the following methods should be mainly adopted according to different data conditions: (1) When there is sufficient runoff data at the station site, frequency analysis and calculation should be carried out; (2) When there are runoff reference stations upstream and downstream of the station site, in the basin, adjacent basins, or in nearby hydrological and meteorological areas with similar characteristics, the frequency analysis and calculation results of the reference stations should be scaled and transferred according to the proportion of the catchment area; (3) When there are no above data conditions, regional comprehensive analysis and calculation should be carried out. 2.0.3 In the n-item continuous runoff series, the m-th empirical frequency Pm arranged in descending order is calculated using the mathematical expectation formula:
×100%
Px=n+i
The runoff frequency curve adopts the Pearson type; when the frequency curve is deduced based on the empirical frequency points, the "three-point method" can generally be used, or it can be fitted by an electronic computer. 2.0.4 When the measured runoff data is insufficient, the interpolation and extension of the runoff series should be considered first, and then the frequency analysis and calculation should be performed; the continuous runoff series used for frequency analysis and calculation should generally not be less than 20 years; the relevant parameters of the interpolated and extended runoff series should have at least 5 years of continuous or discontinuous synchronous measured series. 2.0.5 The interpolation and extension of the runoff series can be based on the data in the upstream and downstream, the basin, the adjacent basin or the nearby hydrological and meteorological similar areas, using the catchment area ratio, water level flow correlation, precipitation runoff correlation, runoff correlation or other verified methods.
2.0.6 The frequency analysis and calculation results of the reference stations and the interpolation and extension of the runoff series by using the method of scaling the catchment area ratio should meet the following requirements:
(1) The geology, topography, vegetation conditions and human activities of the simulated basins are basically the same or similar; (2) The difference in catchment area generally does not exceed 50%; (3) The catchment area comparison results are further corrected by multi-year average precipitation or corresponding precipitation ratio. 2.0.7 In the case of regional comprehensive analysis and calculation, in addition to using the current regional comprehensive charts in accordance with the principles of Article 1.0.4, the following relationships should be further analyzed and synthesized based on data conditions, engineering design needs and work depth: (1) The relationship between regional natural annual runoff and catchment area, (2) The relationship between regional annual precipitation and annual runoff. 2.0.8 The annual runoff series that have been determined for use must be analyzed for representativeness and consistency. The main method for analyzing the representativeness of the annual runoff series should be to directly make a long series of annual precipitation process lines and 10-year sliding mean curves of rainfall stations in the basin, in a hydrological and meteorological similar area, or in a climate consistent area, analyze the annual precipitation cycle change law, and compare the statistical parameters of the long series and the short series synchronized with the annual runoff series. The main method for analyzing the consistency of the annual runoff series should be to analyze the interannual changes in the relationship between annual precipitation and runoff in the basin, or to investigate and understand the historical development of water conservancy and hydropower projects in the basin. 2.0.9 In addition to general evaluation, the representativeness and consistency analysis of the annual runoff series should also specifically determine qualitatively or quantitatively: (1) the impact of human activities on annual runoff; (2) the series mean level;
(3) the future runoff situation.
2.0.10 According to the design guarantee rate of the power station and the data conditions, the annual runoff frequencies of the three representative years of flood, normal and dry seasons can be taken as 5%~25%, 50% and 75%~95% respectively.
2.0.11 The annual distribution and monthly distribution of the design representative year shall be determined by scaling the measured typical year (design typical year) with an empirical frequency close to the design frequency at the same multiple; the design typical year shall be selected from the typical year with complete or relatively complete measured runoff data within the month and which is relatively unfavorable to the future operation of the power station. SL7794
2.0.12 When measured runoff data are scarce, the annual runoff of the design representative year and its annual or monthly distribution shall be determined according to different precipitation and runoff data conditions using the following methods: (1) Directly or after integration, use the reference station data according to the proportion of the catchment area. (2) Use the existing runoff regional comprehensive chart. (3) From the design typical years of annual precipitation with similar frequencies at the precipitation reference station, select the year with measured runoff data as the annual runoff design typical year; the corresponding design representative year runoff shall be determined using regional comprehensive methods. (4) In the absence of the above data conditions, in places where the annual distribution of precipitation and runoff has a good relationship, the annual distribution of the design representative year can be determined based on the percentage of monthly precipitation in the typical year of the precipitation reference station to the annual precipitation, plus an appropriate amount of base flow.
2.0.13 In the correlation analysis, no trans-correlation shall be performed, and it is generally not necessary to calculate the correlation coefficient and select the regression equation. The quality of the correlation relationship can be directly judged by the relevant map; after analyzing and processing the individual prominent points, the line can be set manually and the value can be read on the map.
2.0.14 When the human activities in the basin above the station site have a large impact, it is generally not appropriate to perform annual runoff restoration calculations; however, when there is no human activity impact or the impact is small and it is necessary to transfer the runoff reference station data, the natural annual runoff restoration problem of the reference station should be considered.
2.0.15 For runoff series that are greatly affected by human activities, it is generally not appropriate to perform frequency calculations. Instead, the actual runoff characteristics that reflect the actual situation should be quantitatively determined by the following methods based on the length of the series before and after being greatly affected by water conservancy and hydropower projects in the basin: (1) Runoff calculation methods when measured runoff data are scarce; (2) Analysis and comparison of changes in the relationship between annual precipitation and runoff in the basin; (3) Direct statistical analysis of measured runoff series after being greatly affected by human activities. 2.0.16 In addition to human activities, the design of runoff for small hydropower stations should pay attention to the impact of complex topography (such as extremely uneven or extremely unstable river channels), special geological conditions (such as karst) and sudden natural events (such as floods and dam breaches) on runoff. 2.0.17 For small hydropower cascade power stations, irrigation canal power stations, water storage power stations and power stations that divert water across river basins, the runoff can generally be designed in accordance with this chapter. When the upper power station of a cascade power station has a significant impact on the cascade hydrological situation, the runoff of each power station should be calculated based on the water discharge and diversion method of the power station, the size of the interval catchment area and relevant data. 3 Flow duration curve
3.0.1 For hydrological analysis and calculation of small hydropower stations, the daily average flow duration curve of the design sections such as the water intake section of the power station, the dam site section or the reservoir section should be provided.
3.0.2 To derive the daily average flow duration curve, the following methods are mainly used according to different data conditions: (1) Apply the total daily average flow of the three annual runoff design representative years of wet, normal and dry years, and make statistics in a graded or non-graded queue;
(2) Directly scale and transfer the daily average flow duration curve of the runoff reference station according to the proportion of the catchment area and the proportion of the multi-year average annual precipitation;
(3) Comprehensive regional daily average flow duration curve. 320
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3.0.3 When measured runoff data are scarce, the following methods can be used to derive the daily average flow duration curve according to different data conditions:
(1) Directly statistically analyze the daily average flow of the three typical design years of runoff in the design years of high, medium and low water without scaling at the same ratio;
(2) Only statistically analyze the daily average flow of the representative year of annual runoff or the typical year of average water close to the representative year of average water; (3) First derive the monthly average flow duration curve, and then convert the monthly average flow duration curve into the daily average flow duration curve through comparative analysis of the daily and monthly average flow duration curves of the runoff reference station or the regional comprehensive. 3.0.4 The derivation of the daily average flow duration curve should be based on the results of runoff analysis and calculation. The design runoff results used must be analyzed for series representativeness, consistency and human activity impact. 3.0.5 The flow guarantee rate is still calculated using the mathematical expectation formula of the empirical frequency (2.0.3). 3.0.6 According to the data conditions and the needs of power station planning and design, the following forms of flow duration curves can be further derived or synthesized:
(1) Daily average flow duration curves of each design frequency (2) Daily average flow duration curves during the dry season; (3) "Daily average flow ~ multi-year average flow (or catchment area) ~ guarantee rate" relationship curve. 3.0.7 The graphical flow duration curve should be drawn using appropriate ordinary grid paper or logarithmic grid paper according to the flow amplitude, the form of the flow duration curve and the needs of actual analysis and calculation work. 4 Low-water analysis
4.0.1 In addition to the dry season runoff and flow duration curves, the hydrological analysis and calculation of small hydropower should, based on the data conditions and engineering design requirements, provide the following low-water analysis results in whole or in part: (1) General rules and abnormal changes of annual low water, including the runoff and minimum daily average flow in normal water year (or multi-year average), dry year, dry period of extremely dry year, continuous driest 3 or 2 months and driest month; (2) General rules and abnormal changes of interannual low water, including the periodic rules of dry year, extremely dry year and continuous dry year;
(3) The impact of human activities on low-water runoff; (4) Assessment of future low-water runoff situation.
4.0.2 Low-water analysis should be conducted on the basis of the results of runoff analysis and calculation and derivation of flow duration curves; in addition to investigating low water in combination with flood survey and site investigation, a special low water survey should also be conducted during the dry season. 4.0.3 Field work in special low-water surveys can be carried out during the dry season of the year when there is long-term drought and no rain. In addition to general descriptions, the main contents of the survey should include: low-water level and flow of the river at the time of the survey; the year, occurrence time, water level, flow, and duration of historical low water, or the year, occurrence time, and duration of river dry-up and interruption of flow; the impact of human activities on low water.
4.0.4 The low-water flow level measured during the survey should be determined by comparative analysis based on the annual and dry-season precipitation series of the representative rainfall stations or precipitation reference stations in the basin and the corresponding annual and dry-season precipitation or dry-no-rain conditions of the year. SL77—94
5 Design flood
5.0.1 The hydrological analysis and calculation of small hydropower stations shall provide all or part of the following design flood results based on the data conditions and engineering design requirements:
(1) Annual maximum flood peak flow of each design frequency; (2) Phased maximum flood peak flow of each design frequency; (3) Annual and phased design flood process lines of each design frequency. 5.0.2 The design flood of small hydropower stations shall be carried out in accordance with the main principles, contents and methods of the "Specifications for Design Flood Calculation of Water Conservancy and Hydropower Projects"; however, the requirements may be appropriately lowered and simplified in light of the characteristics of small hydropower stations. 5.0.3 The design flood standards for powerhouses, water diversion and water transmission structures, and water retaining and discharge structures of small hydropower stations shall comply with the provisions of the "Grade Classification and Design Standards for Water Conservancy and Hydropower Projects" ("Mountainous and Hilly Areas" and "Plain and Coastal Areas", SDJ12-78 and SDJ217-87, for trial implementation) and its "Supplementary Provisions", and shall be determined or selected comprehensively according to specific circumstances. 5.0.4 When there is sufficient measured flood data at the site or near its upstream and downstream, frequency analysis and calculation shall be carried out in accordance with the relevant provisions of the "Specifications for Calculation of Design Floods for Water Conservancy and Hydropower Projects", and the design flood shall be directly deduced based on the measured flood data. 5.0.5 When there is a shortage of measured flood data at the site or near its upstream and downstream, the design flood shall be indirectly deduced from the design rainstorm mainly based on the approved comprehensive research results of rainstorms and runoff generation and confluence regions in the whole country and each province (autonomous region, municipality) and their supporting calculation charts (hereinafter referred to as "rainstorm and flood calculation charts" or "charts"). 5.0.6 When the design flood is deduced from the design rainstorm, the design rainfall shall be determined based on the rainstorm and flood calculation charts; the design rainfall type, runoff generation and confluence parameters and design flood process lines, in addition to the application of the regional comprehensive results of the rainstorm and flood calculation charts, shall be selected based on the analysis and comprehensive selection of measured rainstorm and flood data from the reference stations, if conditions permit. 5.0.7 The duration of the designed flood-forming rainstorm for small hydropower stations can generally be 24 hours; however, the short-duration peak rainstorm period controlled by the same frequency in the designed rain pattern should be reasonably determined based on the size of the catchment area of the station site and the analysis and comprehensive results of the measured rainstorm and flood data of the reference observation station.
5.0.8 In order to conveniently and accurately determine the amount of each designed short-duration rainstorm, the "rainstorm duration-frequency-rainfall relationship" line of the designed basin can be drawn on double-logarithmic grid paper based on the calculated data of the long and short-duration rainstorm contour maps of the whole country and each province (municipality, autonomous region).
5.0.9 When there is a shortage of measured rainstorm and flood data at the site or its upstream and downstream, and it is impossible to determine the rainstorm and flood parameters of the design basin, the "measured and investigated flood peak flow modulus (M) ~ catchment area (F) ~ recurrence period (N)* relationship line" of each reference station in the region can be drawn on double logarithmic grid paper, and the design flood of small hydropower stations can be estimated using the regional comprehensive method. 5.0.10 The design flood of small hydropower stations must take into account the investigated historical floods. Reliable or relatively reliable extremely large or large historical floods should be used to participate in frequency calculations, or to verify the design floods determined by regional comprehensive results, or to assist in deriving the water level and flow relationship curve. When the data conditions are very difficult, they can be directly used as design floods. 5.0.11 When there are already investigated flood results at the site or its upstream and downstream, they can be directly quoted from the relevant data published by the province (autonomous region, municipality), otherwise a flood survey should be conducted in the river section of the site; for power stations with greater impact, even if there are published river section flood survey results, it is still necessary to Conduct investigation and review. 322
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5.0.12 Small hydropower flood investigation data and peak flow calculation results should be organized according to the main content and chart format stipulated in the "Trial Measures for Review, Compilation and Publication of Flood Investigation Data" issued by the former Ministry of Water Resources and Electric Power in 1979, and attached to the hydrological analysis and calculation report.
5.0.13 The peak flow of the investigated flood can generally be estimated using the gradient method formula. When conditions permit, it should be within a certain distance from the station site. In the river section with a distance of 100 to 300 m upstream and downstream, two or more flood marks shall be verified, two calculation sections shall be arranged, and the peak flow shall be estimated by the arithmetic average of the two sections or the gradient method of the two sections. 5.0.14 The design flood of a small hydropower cascade power station shall be estimated based on the layout of the cascade hub, the discharge or diversion method of the power station, and the size of the interval catchment area, and the combined flood of the interval design flood and the design flood of the same frequency discharged after regulation by the upper power station.
6 Water level flow relationship
6.0.1 The water level-flow relationship of the design section of the power station shall not be directly transferred from the relationship of other sections in the river. When there are hydrological stations near the upstream and downstream of the station site, the water surface curve or water surface gradient of the river section under each representative water level should be analyzed by setting up temporary water gauge observation or by investigation and measurement, and the existing water level-flow relationship of the hydrological station should be indirectly quoted after the water level is corrected. 6.0.2 When there is no hydrological station in the river section of the station site, the corresponding flow under each assumed water level should be calculated using the single section gradient method formula based on the river section longitudinal section diagram and the design section cross-section diagram, with reference to the average gradient of the main channel riverbed and the measured water surface gradient and estimated flow during flood and low water surveys, and a "calculated" water level-flow relationship should be established. 6.0.3 In the preliminary design stage, whether it is "indirectly quoted" or "calculated" design section water level-flow relationship, it should be verified by measuring the flow at low, medium and high water levels at the station site. 6.0.4 For the non-single water level-discharge relationship of the small hydropower station site affected by backwater, scouring and silting, flood fluctuations, aquatic plant growth, etc., observation and analysis or actual measurement verification should be carried out. If the degree of dispersion of the relevant point group is not large, the average relationship can generally be taken. 6.0.5 The design section large section measurement, river section and river channel longitudinal section measurement and flow measurement should generally be carried out in accordance with the current hydrological measurement specifications in my country.
7 Sediment, evaporation, ice conditions and others
7.0.1 For small hydropower station sites with high sediment content throughout the year and high sediment content during flood season, all or part of the following sediment calculation results should be provided based on data conditions and engineering design requirements: (1) Multi-year average and representative years of design sediment content, sediment transport rate and their annual distribution in rich, medium and low sediment conditions;
(2) Multi-year average and representative years of design sediment content, maximum cross-sectional average suspended sediment content and their occurrence months;
(3) Multi-year average suspended sediment particle size distribution or average particle size and maximum particle size; (4) Qualitative description of the bedload during flood season. SL77-94
7.0.2 Calculation of suspended sediment in small hydropower stations mainly adopts the following methods according to different data conditions: 323
(1) When there is a sediment reference station upstream or downstream of the station or in the basin, the sediment characteristic value of the reference station is directly transferred; (2) When there are other basins around the location of the sediment reference station, the ratio of the multi-year average annual precipitation or annual runoff of the reference flow piers between the design basins is used to scale the sediment characteristic value of the reference station; (3) When there are no above data conditions, the existing sediment regional comprehensive chart is used; if necessary, temporary measurement is carried out. 7.0.3 Suspended sediment frequency analysis calculation method and requirements, etc., the same year runoff and flood rate analysis and calculation. 7.0.4 For general reservoir power stations, hydrological analysis of small hydropower stations should provide the multi-year average water surface evaporation and land surface evaporation of the design site and its annual distribution based on the evaporation reference station data or existing regional comprehensive charts of evaporation in the basin or in a similar hydrological and meteorological area.
7.0.5 In northern my country, hydrological analysis and calculation of small hydropower stations should provide the ice characteristics of the site based on hydrological and meteorological data such as local hydrological characteristics statistics, including: river conditions during freezing and thawing; the appearance of bank ice, drift ice, freezing of the entire river, the earliest, latest and multi-year average dates of ice melting; ice thickness during freezing period; ice jams, ice dams and drift ice sizes and their possible hazards.
7.0.6 In karst geological areas, hydrological analysis and calculation of small hydropower stations should provide hydrochemical data of the site, mainly the corrosive free CO2 and HCO2 that have a serious destructive effect on turbines; plasma content and its seasonal variation law. 8.0.1 The design runoff, design flood, flow duration curve and water level flow relationship results must be checked for rationality; the single station single analysis and calculation results that have not been checked for rationality shall not be listed as formal results. 8.0.2 The rationality check of the results should use all the measured data and analysis and calculation results of all reference stations and design sites, adopt several estimation and deduction methods, conduct surface distribution law research on the results of the same method at multiple stations and comparative analysis of the results of multiple methods at a single station, and determine the formal results based on the principle of one method as the main method, multiple method comparison, comprehensive analysis, and reasonable selection.
8.0.3 The parameters or items for the rationality check of the results should mainly include: annual runoff mean; design peak flow and flood volume; investigate the flood peak flow and riverbed roughness\value in the calculation formula of the gradient method; the shape and characteristics of the flow duration curve and the water level flow relationship curve; and the low water guaranteed flow. 8.0.4 When conditions permit, in addition to the design frequency or design guarantee rate results specified by the engineering design, the results of all major frequencies or guarantee rates can be presented in diagrams and tables; at the same time, a comprehensive chart of runoff and flood in the basin or region can be further made to provide important tools and means for checking the rationality of the results and solving the hydrological analysis and calculation of the site without data. 8.0.5 The mean annual runoff and design flood peak flow data analyzed and calculated by various methods should be basically the same, and should be basically coordinated with the national or local regional comprehensive contour map, related curves or empirical formulas. The distribution on the basin, region, upstream and downstream of the river, main and tributary rivers, etc. is basically reasonable and basically corresponds to the spatial variation of precipitation. 8.0.6 When the results of several methods differ greatly in value (for example, more than 15%), or there is an obviously unreasonable regional distribution that cannot be explained, or there is a large contradiction with the spatial variation of precipitation, the cause should be carefully found, the results should be adjusted, and the analysis and calculation should be re-analyzed when necessary.
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8.0.7 Special attention should be paid to the rationality check of the results of the investigation flood peak flow estimation. The inspection mainly compares: the spatial distribution of floods and rainstorms in the same year at each station, the size arrangement of floods in different years at the same station; the magnitude of the investigation floods with a certain recurrence period and the measured and known investigation floods in the same basin or region. 8.0.8 In order to identify the reasonable magnitude range of the investigation flood peak flow with a certain recurrence period, the regional comprehensive "measured and investigated flood peak flow modulus (M) ~ catchment area (F) ~ recurrence period (N)" relationship can be used for inspection. 8.0.9 If it is found in the rationality check that the estimated value of the investigation flood peak flow is too large or too small, it should first be checked whether the value of the riverbed roughness n in the gradient method formula is reasonable, and the measured data of the reference station should be used for verification and comparison. 8.0.10 For flow duration curves, the relationship between each flow duration curve and the influence of flow amplitude and base flow on the curve shape should be analyzed and checked; for water level flow relationship curves, the relationship between cross-sectional characteristics and curve shape should be compared and coordinated.
Appendix A
Hydrological analysis and calculation of small hydropower stations with installed capacity less than 500 kW and less than 100 kW
A1.0.1 "For power stations with installed capacity less than 500 kW, the content can be appropriately simplified and the requirements can be relaxed according to the actual situation." The main application is to use the existing regional comprehensive charts and conduct flood and low water surveys, and simply provide all or part of the following hydrological analysis and calculation results:
(1) Multi-year average annual runoff and its annual distribution; (2) Low water survey, including estimated low water flow, dry months in the year and their general duration; (3) Design peak flow and its corresponding water level-flow relationship, or investigate the peak water level of floods; (4) General qualitative description of suspended sediment, bedload, ice conditions, annual precipitation, temperature and other general meteorological conditions. In addition to the investigation and understanding of floods, low water and human activities, the work contents such as series representative analysis, derivation of flow duration curves, rationality check of results, and preparation of special hydrological analysis and calculation reports can be omitted. A2.0.1 "For micro power stations less than 100kW, this can be implemented as a reference." For example, the existing district and city comprehensive charts can be read to determine the multi-year average annual runoff or average flow of the station site; the highest flood levels in previous years can be investigated at the station site to determine the elevation of the plant, etc.
Additional Notes
Editor: Rural Electrification Research Institute of the Ministry of Water Resources Main Drafters: Lv Tianshou Li Ji5 Design section large section measurement, river section longitudinal section measurement and flow measurement should generally be carried out in accordance with the current hydrological measurement specifications of my country.
7 Sediment, evaporation, ice conditions and others
7.0.1 For small hydropower station sites with high sediment content throughout the year and high flood and narrow sediment content during the flood season, the following sediment calculation results should be provided in full or in part according to the data conditions and engineering design requirements: (1) Multi-year average and representative years of design sediment content, sediment transport (rate) and their annual distribution in rich, medium and low sediment;
(2) Multi-year average and representative years of design sediment content, medium and low sediment content, and the month of occurrence of the annual maximum cross-section average suspended sediment content;
(3) Multi-year average suspended sediment particle size distribution or average particle size and maximum particle size; (4) Qualitative description of the bedload during the flood season. SL77-94
7.0.2 Calculation of suspended sediment in small hydropower stations mainly adopts the following methods according to different data conditions: 323
(1) When there is a sediment reference station upstream or downstream of the station or in the basin, the sediment characteristic value of the reference station is directly transferred; (2) When there are other basins around the location of the sediment reference station, the ratio of the multi-year average annual precipitation or annual runoff of the reference flow piers between the design basins is used to scale the sediment characteristic value of the reference station; (3) When there are no above data conditions, the existing sediment regional comprehensive chart is used; if necessary, temporary measurement is carried out. 7.0.3 Suspended sediment frequency analysis calculation method and requirements, etc., the same year runoff and flood rate analysis and calculation. 7.0.4 For general reservoir power stations, hydrological analysis of small hydropower stations should provide the multi-year average water surface evaporation and land surface evaporation of the design site and its annual distribution based on the evaporation reference station data or existing regional comprehensive charts of evaporation in the basin or in a similar hydrological and meteorological area.
7.0.5 In northern my country, hydrological analysis and calculation of small hydropower stations should provide the ice characteristics of the site based on hydrological and meteorological data such as local hydrological characteristics statistics, including: river conditions during freezing and thawing; the appearance of bank ice, drift ice, freezing of the entire river, the earliest, latest and multi-year average dates of ice melting; ice thickness during freezing period; ice jams, ice dams and drift ice sizes and their possible hazards.
7.0.6 In karst geological areas, hydrological analysis and calculation of small hydropower stations should provide hydrochemical data of the site, mainly the corrosive free CO2 and HCO2 that have a serious destructive effect on turbines; plasma content and its seasonal variation law. 8.0.1 The design runoff, design flood, flow duration curve and water level flow relationship results must be checked for rationality; the single station single analysis and calculation results that have not been checked for rationality shall not be listed as formal results. 8.0.2 The rationality check of the results should use all the measured data and analysis and calculation results of all reference stations and design sites, adopt several estimation and deduction methods, conduct surface distribution law research on the results of the same method at multiple stations and comparative analysis of the results of multiple methods at a single station, and determine the formal results based on the principle of one method as the main method, multiple method comparison, comprehensive analysis, and reasonable selection.
8.0.3 The parameters or items for the rationality check of the results should mainly include: annual runoff mean; design peak flow and flood volume; investigate the flood peak flow and riverbed roughness\value in the calculation formula of the gradient method; the shape and characteristics of the flow duration curve and the water level flow relationship curve; and the low water guaranteed flow. 8.0.4 When conditions permit, in addition to the design frequency or design guarantee rate results specified by the engineering design, the results of all major frequencies or guarantee rates can be presented in diagrams and tables; at the same time, a comprehensive chart of runoff and flood in the basin or region can be further made to provide important tools and means for checking the rationality of the results and solving the hydrological analysis and calculation of the site without data. 8.0.5 The mean annual runoff and design flood peak flow data analyzed and calculated by various methods should be basically the same, and should be basically coordinated with the national or local regional comprehensive contour map, related curves or empirical formulas. The distribution on the basin, region, upstream and downstream of the river, main and tributary rivers, etc. is basically reasonable and basically corresponds to the spatial variation of precipitation. 8.0.6 When the results of several methods differ greatly in value (for example, more than 15%), or there is an obviously unreasonable regional distribution that cannot be explained, or there is a large contradiction with the spatial variation of precipitation, the cause should be carefully found, the results should be adjusted, and the analysis and calculation should be re-analyzed when necessary.
Rural Hydropower and Electrification Volume·Planning
8.0.7 Special attention should be paid to the rationality check of the results of the investigation flood peak flow estimation. The inspection mainly compares: the spatial distribution of floods and rainstorms in the same year at each station, the size arrangement of floods in different years at the same station; the magnitude of the investigation floods with a certain recurrence period and the measured and known investigation floods in the same basin or region. 8.0.8 In order to identify the reasonable magnitude range of the investigation flood peak flow with a certain recurrence period, the regional comprehensive "measured and investigated flood peak flow modulus (M) ~ catchment area (F) ~ recurrence period (N)" relationship can be used for inspection. 8.0.9 If it is found in the rationality check that the estimated value of the investigation flood peak flow is too large or too small, it should first be checked whether the value of the riverbed roughness n in the gradient method formula is reasonable, and the measured data of the reference station should be used for verification and comparison. 8.0.10 For flow duration curves, the relationship between each flow duration curve and the influence of flow amplitude and base flow on the curve shape should be analyzed and checked; for water level flow relationship curves, the relationship between cross-sectional characteristics and curve shape should be compared and coordinated.
Appendix A
Hydrological analysis and calculation of small hydropower stations with installed capacity less than 500 kW and less than 100 kW
A1.0.1 "For power stations with installed capacity less than 500 kW, the content can be appropriately simplified and the requirements can be relaxed according to the actual situation." The main application is to use the existing regional comprehensive charts and conduct flood and low water surveys, and simply provide all or part of the following hydrological analysis and calculation results:
(1) Multi-year average annual runoff and its annual distribution; (2) Low water survey, including estimated low water flow, dry months in the year and their general duration; (3) Design peak flow and its corresponding water level-flow relationship, or investigate the peak water level of floods; (4) General qualitative description of suspended sediment, bedload, ice conditions, annual precipitation, temperature and other general meteorological conditions. In addition to the investigation and understanding of floods, low water and human activities, the work contents such as series representative analysis, derivation of flow duration curves, rationality check of results, and preparation of special hydrological analysis and calculation reports can be omitted. A2.0.1 "For micro power stations less than 100kW, this can be implemented as a reference." For example, the existing district and city comprehensive charts can be read to determine the multi-year average annual runoff or average flow of the station site; the highest flood levels in previous years can be investigated at the station site to determine the elevation of the plant, etc.
Additional Notes
Editor: Rural Electrification Research Institute of the Ministry of Water Resources Main Drafters: Lv Tianshou Li Ji5 Design section large section measurement, river section longitudinal section measurement and flow measurement should generally be carried out in accordance with the current hydrological measurement specifications of my country.
7 Sediment, evaporation, ice conditions and others
7.0.1 For small hydropower station sites with high sediment content throughout the year and high flood and narrow sediment content during the flood season, the following sediment calculation results should be provided in full or in part according to the data conditions and engineering design requirements: (1) Multi-year average and representative years of design sediment content, sediment transport (rate) and their annual distribution in rich, medium and low sediment;
(2) Multi-year average and representative years of design sediment content, medium and low sediment content, and the month of occurrence of the annual maximum cross-section average suspended sediment content;
(3) Multi-year average suspended sediment particle size distribution or average particle size and maximum particle size; (4) Qualitative description of the bedload during the flood season. SL77-94
7.0.2 Calculation of suspended sediment in small hydropower stations mainly adopts the following methods according to different data conditions: 323
(1) When there is a sediment reference station upstream or downstream of the station or in the basin, the sediment characteristic value of the reference station is directly transferred; (2) When there are other basins around the location of the sediment reference station, the ratio of the multi-year average annual precipitation or annual runoff of the reference flow piers between the design basins is used to scale the sediment characteristic value of the reference station; (3) When there are no above data conditions, the existing sediment regional comprehensive chart is used; if necessary, temporary measurement is carried out. 7.0.3 Suspended sediment frequency analysis calculation method and requirements, etc., the same year runoff and flood rate analysis and calculation. 7.0.4 For general reservoir power stations, hydrological analysis of small hydropower stations should provide the multi-year average water surface evaporation and land surface evaporation of the design site and its annual distribution based on the evaporation reference station data or existing regional comprehensive charts of evaporation in the basin or in a similar hydrological and meteorological area.
7.0.5 In northern my country, hydrological analysis and calculation of small hydropower stations should provide the ice characteristics of the site based on hydrological and meteorological data such as local hydrological characteristics statistics, including: river conditions during freezing and thawing; the appearance of bank ice, drift ice, freezing of the entire river, the earliest, latest and multi-year average dates of ice melting; ice thickness during freezing period; ice jams, ice dams and drift ice sizes and their possible hazards.
7.0.6 In karst geological areas, hydrological analysis and calculation of small hydropower stations should provide hydrochemical data of the site, mainly the corrosive free CO2 and HCO2 that have a serious destructive effect on turbines; plasma content and its seasonal variation law. 8.0.1 The design runoff, design flood, flow duration curve and water level flow relationship results must be checked for rationality; the single station single analysis and calculation results that have not been checked for rationality shall not be listed as formal results. 8.0.2 The rationality check of the results should use all the measured data and analysis and calculation results of all reference stations and design sites, adopt several estimation and deduction methods, conduct surface distribution law research on the results of the same method at multiple stations and comparative analysis of the results of multiple methods at a single station, and determine the formal results based on the principle of one method as the main method, multiple method comparison, comprehensive analysis, and reasonable selection.
8.0.3 The parameters or items for the rationality check of the results should mainly include: annual runoff mean; design peak flow and flood volume; investigate the flood peak flow and riverbed roughness\value in the calculation formula of the gradient method; the shape and characteristics of the flow duration curve and the water level flow relationship curve; and the low water guaranteed flow. 8.0.4 When conditions permit, in addition to the design frequency or design guarantee rate results specified by the engineering design, the results of all major frequencies or guarantee rates can be presented in diagrams and tables; at the same time, a comprehensive chart of runoff and flood in the basin or region can be further made to provide important tools and means for checking the rationality of the results and solving the hydrological analysis and calculation of the site without data. 8.0.5 The mean annual runoff and design flood peak flow data analyzed and calculated by various methods should be basically the same, and should be basically coordinated with the national or local regional comprehensive contour map, related curves or empirical formulas. The distribution on the basin, region, upstream and downstream of the river, main and tributary rivers, etc. is basically reasonable and basically corresponds to the spatial variation of precipitation. 8.0.6 When the results of several methods differ greatly in value (for example, more than 15%), or there is an obviously unreasonable regional distribution that cannot be explained, or there is a large contradiction with the spatial variation of precipitation, the cause should be carefully found, the results should be adjusted, and the analysis and calculation should be re-analyzed when necessary.
Rural Hydropower and Electrification Volume·Planning
8.0.7 Special attention should be paid to the rationality check of the results of the investigation flood peak flow estimation. The inspection mainly compares: the spatial distribution of floods and rainstorms in the same year at each station, the size arrangement of floods in different years at the same station; the magnitude of the investigation floods with a certain recurrence period and the measured and known investigation floods in the same basin or region. 8.0.8 In order to identify the reasonable magnitude range of the investigation flood peak flow with a certain recurrence period, the regional comprehensive "measured and investigated flood peak flow modulus (M) ~ catchment area (F) ~ recurrence period (N)" relationship can be used for inspection. 8.0.9 If it is found in the rationality check that the estimated value of the investigation flood peak flow is too large or too small, it should first be checked whether the value of the riverbed roughness n in the gradient method formula is reasonable, and the measured data of the reference station should be used for verification and comparison. 8.0.10 For flow duration curves, the relationship between each flow duration curve and the influence of flow amplitude and base flow on the curve shape should be analyzed and checked; for water level flow relationship curves, the relationship between cross-sectional characteristics and curve shape should be compared and coordinated.
Appendix A
Hydrological analysis and calculation of small hydropower stations with installed capacity less than 500 kW and less than 100 kW
A1.0.1 "For power stations with installed capacity less than 500 kW, the content can be appropriately simplified and the requirements can be relaxed according to the actual situation." The main application is to use the existing regional comprehensive charts and conduct flood and low water surveys, and simply provide all or part of the following hydrological analysis and calculation results:
(1) Multi-year average annual runoff and its annual distribution; (2) Low water survey, including estimated low water flow, dry months in the year and their general duration; (3) Design peak flow and its corresponding water level-flow relationship, or investigate the peak water level of floods; (4) General qualitative description of suspended sediment, bedload, ice conditions, annual precipitation, temperature and other general meteorological conditions. In addition to the investigation and understanding of floods, low water and human activities, the work contents such as series representative analysis, derivation of flow duration curves, rationality check of results, and preparation of special hydrological analysis and calculation reports can be omitted. A2.0.1 "For micro power stations less than 100kW, this can be implemented as a reference." For example, the existing district and city comprehensive charts can be read to determine the multi-year average annual runoff or average flow of the station site; the highest flood levels in previous years can be investigated at the station site to determine the elevation of the plant, etc.
Additional Notes
Editor: Rural Electrification Research Institute of the Ministry of Water Resources Main Drafters: Lv Tianshou Li Ji6 In karst geological areas, hydrological analysis and calculation of small hydropower stations should provide site water chemistry data, mainly the content of corrosive free CO2 and HCO2 plasma that have serious destructive effects on turbines and their seasonal variation. 8 Results rationality check
8.0.1 The results of design runoff, design flood, flow duration curve and water level flow relationship must be checked for rationality; single-station single-time analysis and calculation results that have not been checked for rationality shall not be listed as formal results. 8.0.2 The results rationality check should use all the measured data and analysis and calculation results of all reference stations and design sites, adopt several estimation and deduction methods, conduct surface distribution law research on the results of the same method at multiple stations and comparative analysis of the results of multiple methods at a single station, and determine the formal results according to the principles of one method as the main method, multiple method comparison, comprehensive analysis, and reasonable selection.
8.0.3 The parameters or items for the rationality check of the results should mainly include: annual runoff mean; design flood peak flow and flood volume; riverbed roughness value in the calculation formula of flood peak flow and its gradient method; flow duration curve and water level flow relationship curve shape and characteristics; low water guaranteed flow. 8.0.4 When conditions permit, in addition to the design frequency or design guarantee rate results specified by the engineering design, the results of all major frequencies or guarantee rates can be given in diagrams and lists; at the same time, a comprehensive chart of runoff and flood in this basin or region can be further made to provide important tools and means for the rationality check of the results and the solution of hydrological analysis and calculation of sites without data. 8.0.5 The design annual runoff mean and design flood peak flow data analyzed and calculated by various methods should be basically the same, and should be basically coordinated with various national or local regional comprehensive contour maps, related curves or empirical formulas, and the distribution on the basin, region, upstream and downstream of the river, main and tributary rivers should be basically reasonable, and basically corresponding to the spatial changes in precipitation. 8.0.6 When the results of several methods differ greatly in value (for example, more than 15%), or there is an obviously unreasonable regional distribution that cannot be explained, or there is a big contradiction with the spatial variation of precipitation, the reasons should be carefully found, the results should be adjusted, and the analysis and calculation should be re-analyzed when necessary.
Rural Hydropower and Electrification Volume·Planning
8.0.7 Special attention should be paid to the rationality check of the results of the flood peak flow estimation of the survey flood. The check mainly compares: the spatial distribution of floods and rainstorms in the same year at each site, the size arrangement of floods in different years at the same site; the magnitude of the survey floods with a certain recurrence period and the measured and known survey floods in the same basin or region. 8.0.8 In order to identify the reasonable magnitude range of the flood peak flow of the survey flood with a certain recurrence period, the regional comprehensive "measured and surveyed flood peak flow modulus (M) ~ catchment area (F) ~ recurrence period (N)" relationship can be used for inspection. 8.0.9 If the estimated value of the flood peak flow of the investigated flood is found to be too large or too small during the rationality check, the first thing to do is to check whether the value of the riverbed roughness n in the gradient method formula is reasonable, and to verify and compare it with the measured data of the reference measuring station. 8.0.10 For the flow duration curve, the relationship between the flow duration curves and the influence of the flow amplitude and base flow on the curve shape should be analyzed and checked; for the water level flow relationship curve, the relationship between the cross-sectional characteristics and the curve shape should be compared and coordinated.
Appendix A
Hydrological analysis and calculation of small hydropower stations with installed capacity less than 500 kW and less than 100 kW
A1.0.1 "For power stations with installed capacity less than 500 kW, the content can be appropriately simplified and the requirements can be relaxed according to the actual situation." The main application is to use the existing regional comprehensive charts and conduct flood and low water surveys, and simply provide all or part of the following hydrological analysis and calculation results:
(1) Multi-year average annual runoff and its annual distribution; (2) Low water survey, including estimated low water flow, dry months in the year and their general duration; (3) Design peak flow and its corresponding water level-flow relationship, or investigate the peak water level of floods; (4) General qualitative description of suspended sediment, bedload, ice conditions, annual precipitation, temperature and other general meteorological conditions. In addition to the investigation and understanding of floods, low water and human activities, the work contents such as series representative analysis, derivation of flow duration curves, rationality check of results, and preparation of special hydrological analysis and calculation reports can be omitted. A2.0.1 "For micro power stations less than 100kW, this can be implemented as a reference." For example, the existing district and city comprehensive charts can be read to determine the multi-year average annual runoff or average flow of the station site; the highest flood levels in previous years can be investigated at the station site to determine the elevation of the plant, etc.
Additional Notes
Editor: Rural Electrification Research Institute of the Ministry of Water Resources Main Drafters: Lv Tianshou Li Ji6 In karst geological areas, hydrological analysis and calculation of small hydropower stations should provide site water chemistry data, mainly the content of corrosive free CO2 and HCO2 plasma that have serious destructive effects on turbines and their seasonal variation. 8 Results rationality check
8.0.1 The results of design runoff, design flood, flow duration curve and water level flow relationship must be checked for rationality; single-station single-time analysis and calculation results that have not been checked for rationality shall not be listed as formal results. 8.0.2 The results rationality check should use all the measured data and analysis and calculation results of all reference stations and design sites, adopt several estimation and deduction methods, conduct surface distribution law research on the results of the same method at multiple stations and comparative analysis of the results of multiple methods at a single station, and determine the formal results according to the principles of one method as the main method, multiple method comparison, comprehensive analysis, and reasonable selection.
8.0.3 The parameters or items for the rationality check of the results should mainly include: annual runoff mean; design flood peak flow and flood volume; riverbed roughness value in the calculation formula of flood peak flow and its gradient method; flow duration curve and water level flow relationship curve shape and characteristics; low water guaranteed flow. 8.0.4 When conditions permit, in addition to the design frequency or design guarantee rate results specified by the engineering design, the results of all major frequencies or guarantee rates can be given in diagrams and lists; at the same time, a comprehensive chart of runoff and flood in this basin or region can be further made to provide important tools and means for the rationality check of the results and the solution of hydrological analysis and calculation of sites without data. 8.0.5 The design annual runoff mean and design flood peak flow data analyzed and calculated by various methods should be basically the same, and should be basically coordinated with various national or local regional comprehensive contour maps, related curves or empirical formulas, and the distribution on the basin, region, upstream and downstream of the river, main and tributary rivers should be basically reasonable, and basically corresponding to the spatial changes in precipitation. 8.0.6 When the results of several methods differ greatly in value (for example, more than 15%), or there is an obviously unreasonable regional distribution that cannot be explained, or there is a big contradiction with the spatial variation of precipitation, the reasons should be carefully found, the results should be adjusted, and the analysis and calculation should be re-analyzed when necessary.
Rural Hydropower and Electrification Volume·Planning
8.0.7 Special attention should be paid to the rationality check of the results of the flood peak flow estimation of the survey flood. The check mainly compares: the spatial distribution of floods and rainstorms in the same year at each site, the size arrangement of floods in different years at the same site; the magnitude of the survey floods with a certain recurrence period and the measured and known survey floods in the same basin or region. 8.0.8 In order to identify the reasonable magnitude range of the flood peak flow of the survey flood with a certain recurrence period, the regional comprehensive "measured and surveyed flood peak flow modulus (M) ~ catchment area (F) ~ recurrence period (N)" relationship can be used for inspection. 8.0.9 If the estimated value of the flood peak flow of the investigated flood is found to be too large or too small during the rationality check, the first thing to do is to check whether the value of the riverbed roughness n in the gradient method formula is reasonable, and to verify and compare it with the measured data of the reference measuring station. 8.0.10 For the flow duration curve, the relationship between the flow duration curves and the influence of the flow amplitude and base flow on the curve shape should be analyzed and checked; for the water level flow relationship curve, the relationship between the cross-sectional characteristics and the curve shape should be compared and coordinated.
Appendix A
Hydrological analysis and calculation of small hydropower stations with installed capacity less than 500 kW and less than 100 kW
A1.0.1 "For power stations with installed capacity less than 500 kW, the content can be appropriately simplified and the requirements can be
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