Utilization of Time-Based Meteorological Droughts to Investigate Occurrence of Streamflow Droughts

Complexities of streamflow drought analyses motivate utilization of simple, alternative methods, which can provide timely information for effective water resources management. For this purpose time-based meteorological drought characteristics, identified by SPI _{3 − month} , SPI _{6 − month} and SPI _Anuual are investigated. A boxplot approach is used to exclude non-rainy months from the analysis. Streamflow drought characteristics are described by drought intensities, and are calculated by the threshold level method. The non-parametric Wilcoxon–Mann–Whitney test is used to investigate relations between streamflow drought intensities and SPI _{3 − month} , SPI _{6 − month} and SPI _Anuual . The study area is the Doroodzan Watershed and Reservoir in southwestern Iran, with four rain gauge and two hydrometric stations. According to the results, most of time-based SPI values show significant relations (at 5% level of significance) with streamflow drought intensities. However, the most significant relation is between SPI _Anuual of Jamalbeik rain gauge station (centrally located in the study area) and drought intensities of Chamriz hydrometric station (located at the reservoir inlet). Comparison of study results with available records of documented droughts, confirms applicability of the proposed procedures. The SPI _Anuual is based on one-year-ahead moving average rainfalls. Then, SPI _Anuual of Jamalbeik station can be used to investigate occurrence of streamflow drought in Chamriz hydrometric station.     

Climate Variability Influences on Hydrological Responses of a Large Himalayan Basin

The hydrological cycle, a fundamental component of climate is likely to be altered in important ways due to climate change. In this study, the historical daily runoff has been simulated for the Chenab River basin up to Salal gauging site using a simple conceptual snowmelt model (SNOWMOD). The model has been used to study the impact of plausible hypothetical scenarios of temperature and rainfall on the melt characteristics and daily runoff of the Chenab River basin. The average value of increase in snowmelt runoff for T + 1°C, T + 2°C and T + 3°C scenarios are obtained to be 10, 28 and 43%, respectively. Whereas, the average value of increase in total streamflow runoff for T + 1°C, T + 2°C and T + 3°C are obtained to be 7, 19 and 28%, respectively. Changes in rainfall by −10 and + 10% vary the average annual snowmelt runoff over the T + 2°C scenario by −1% and + 1% only. The result shows that melt is much more sensitive to increase in temperature than to rainfall.     

Hantush’s M(α, β) and M*(α, β) are Generalized Incomplete Exponential Functions

It is pointed out that Hantush’s M(α, β) and M*(α, β) functions, two functions that arise with respect to groundwater pumping modeling, are particular cases of the generalized incomplete exponential functions known in the mathematics/statistics literature. Some relevant computational issues are discussed.     

Bearing capacity of an arch dam

Results of investigation of variations in the stress-strain state of an “arch-dam–rock-bed” system on approaching the first limiting state (loss of the system’s bearing capacity) are analyzed. Translated from Gidrotekhnicheskoe Stroitel‘stvo, No. 9, September 2008, pp. 16–30.     

Comparability Analyses of the <Emphasis Type="Italic">SPI</Emphasis> and <Emphasis Type="Italic">RDI</Emphasis> Meteorological Drought Indices in Different Climatic Zones

Comparability analyses are performed to investigate similarities/differences of the standard precipitation index (SPI) and the reconnaissance drought index (RDI), respectively, utilizing precipitation and ratio of precipitation over potential evapotranspiration (ET ₀). Data are from stations with different climatic conditions in Iran. Drought characteristics of the 3-month, 6-month and annual SPI and RDI time series are developed and Markov chain order dependencies are investigated by the Log-likelihood, AIC and BIC tests. Steady state probabilities and Markov chain characteristics, i.e., expected residence time in different drought classes and time to reach “Near Normal” class are investigated. According to results, both indices exhibit an overall similar behaviour; particularly, they follow the first order Markov chain dependency. However, climatic variability may produce some differences. In several cases, the “Extremely Dry” class has received a more critical value by RDI. Furthermore, the expected residence time of “Near Normal” class and expected time to reach “Near Normal” class are quite different in a number of cases. The results show that the RDI by utilizing the ET ₀ can be very sensitive to climatic variability. This is rather important, since if the drought analyses are for agricultural applications, utilization of the RDI would seem to serve a better purpose.     

Condition and control of the thermal-filtration regime of northern rock-and-earthfill dams constructed in accordance with the thaw principle

Characteristic specific features of the thermal regime of the “dam-bed” system are examined. __________ Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 2, February 2008, pp. 54–58.     

Nomograms for preliminary design of pressure tunnel linings

Conclusions By means of the proposed nomograms it is possible to select at preliminary stages of design the economically advantageous types and dimensions of linings of tunnels being driven in isotropic rocks. From an examination of the solutions obtained from the nomograms, we can draw the following conclusions, which have also been included in the “Instructions on the Designing of Hydraulic Tunnels,” namely: a) it is recommended to use concrete linings in tunnels with an inside diameter up to 6 m in rocks withf _st=2–10 at internal water pressure heads not exceeding 20–90 m, respectively; here it is recommended to take into account the economy of labor expenditures in comparison with other types of linings; b) reinforced-concrete linings should be used: in weak rocks (f _st=0.5–1.0) at internal water heads to 40 m and in stronger rocks (f _st≥2) for tunnels with D_i=5 and greater at heads to 50 m, and in strong rocks (f _st=15) to 140 m; c) two-layer linings with an inner reinforced-gunite ring up to 15 cm thick should be used at heads of 50 m and greater in rock of medium strength and higher (f _st≥3); d) two-layer linings with an inner steel shell should be used in granular and soft rocks (f _st=0.5–1.0) with D_i≥10 m, and also at neads of 40 m and greater for any tunnel sections in these rocks and in cases of the economic inexpediency or structural impossibility of using other types of linings. Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 4, pp. 15–19, April, 1973.     

Adaptation to Climate Change in the Management of a Canadian Water-Resources System Exploited for Hydropower

The management adaptation potential of the Peribonka River water resource system (Quebec, Canada) is investigated in the context of the evolution of climate change. The objective of this study is to evaluate the impacts on hydropower, power plant efficiency, unproductive spills and reservoir reliability due to changes in the hydrological regimes. The climate change projections used here are from the Canadian regional climate model (CRCM) nested by the Canadian-coupled global climate model (CGCM3) forced with the SRES A2 greenhouse gas emission scenario. The hydrological regimes were simulated with the distributed hydrological model Hydrotel. They were incorporated into a dynamic and stochastic optimization model in order to adapt the operating rules of the water resource system annually, according to the evolution of the climate. The impacts were analyzed over the years 1961–2099, split into four periods for comparison purposes: control period (1961–1990), horizon 2020 (2010–2039), horizon 2050 (2040–2069) and horizon 2080 (2070–2099). The main results indicate that annual mean hydropower would decrease by 1.8% for the period 2010–2039 and then increase by 9.3% and 18.3% during the periods 2040–2069 and 2070–2099, respectively. The trend to increase is statistically significant starting from 2061 (Mann–Kendall with p = 5%). The change in the mean annual production is statistically significant for the 2040–2069 and 2070–2099 periods (t-test with p = 5%). Also, the change in the variance is significant for the periods 2010–2039, 2040–2069 and 2070–2099 (F-test). Annual mean unproductive spills would increase from 1961–2099, but the trend is not statistically significant. However, the changes in the variance of the annual mean spills are significant in the periods 2010–2039, 2040–2069 and 2070–2099. Overall, the reliability of a reservoir would decrease and the vulnerability increase as the climate changes.     

Pareto Random Variables for Hydrological Modeling

Motivated by hydrological problems, the exact distributions of the sum X + Y, the product X Y and the ratio X/(X + Y) are derived when X and Y are independent Pareto random variables. A detailed application of the results is provided to extreme rainfall data from Florida.     

Standardization of the strength of large-lump soils

The law governing variation in soil properties is examined. Translated from Gidrotechnicheskoe Stroitel‘stvo, No. 2, February 2009, pp. 4–12.     

Substantiation of parameters of horizontal fish-discharging reticulated barriers

Parameters of plane and curvilinear reticulated fish-discharging barriers are substantiated. Translated from Gidrotekhnicheskoe Stroitel‘stvo, No. 7, July 2008, pp. 50 – 54.     

Hydraulic operating conditions of an eddy tunnel outlet with an inclined shaft

Model studies of the hydraulic operating conditions of an eddy tunnel outlet with an inclined shaft showed that:

Substantiation of the Strength and Stability of Concrete Dams Based on the Solution of a Nonlinear Three-Dimensional Problem

An analysis of methods of nonlinear computation of concrete dams is presented, which makes it possible to determine the margin of the bearing capacity of the “structure – foundation” system. __________ Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, May 2005, pp. 42 – 45.     

Soil Erosion Assessment in a Hilly Catchment of North Eastern India Using USLE, GIS and Remote Sensing

In the present study, soil erosion assessment of Dikrong river basin of Arunachal Pradesh (India) was carried out. The river basin was divided into 200 × 200 m grid cells. The Arc Info 7.2 GIS software and RS (ERDAS IMAGINE 8.4 image processing software) provided spatial input data and the USLE was used to predict the spatial distribution of the average annual soil loss on grid basis. The average rainfall erositivity factor (R) for Dikrong river basin was found to be 1,894.6 MJ mm ha⁻¹ h⁻¹ year⁻¹. The soil erodibility factor (K) with a magnitude of 0.055 t ha h ha⁻¹ MJ⁻¹ mm⁻¹ is the highest, with 0.039 t ha h ha⁻¹ MJ⁻¹ mm⁻¹ is the least for the watershed. The highest and lowest value of slope length factor (LS) is 53.5 and 5.39 respectively for the watershed. The highest and lowest values of crop management factor (C) were found out to be 0.004 and 1.0 respectively for the watershed. The highest and lowest value of conservation factor (P) were found to be 1 and 0.28 respectively for the watershed. The average annual soil loss of the Dikrong river basin is 51 t ha⁻¹ year⁻¹. About 25.61% of the watershed area is found out to be under slight erosion class. Areas covered by moderate, high, very high, severe and very severe erosion potential zones are 26.51%, 17.87%, 13.74%, 2.39% and 13.88% respectively. Therefore, these areas need immediate attention from soil conservation point of view.     

Main principles for construction of relay protection of 330–750-kV equipment with the use of microprocessor devices of series Shé2710

The basic principles for construction of relay protection of the equipment of 330–750-kV networks and substations with the use of microprocessor devices of series Shé2710 produced by the “éKRA” Research and Production Enterprise (Cheboksary) are considered. __________ Translated from élektricheskie Stantsii, No. 9, September 2005, pp. 42–45.     

On methods of calculating potential (seepage) flows on the basis of Jacobi elliptic integrals

Simplified analytical relationships, which make it possible to determine elliptic integrals in calculating various schemes of potential (seepage) flows, are proposed. Translated from Gidrotekhnicheskoe Stroitel‘stvo, No. 8, August 2008, pp. 5–7.     

Operation of the dam of the Bureiskaya HPP during filling of the reservoir

Operation of the dam in a transitional mode is described. __________ Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 1, January 2006, pp. 8–15.     

Verification of the earthquake resistance of the arch-gravity dam of the Sayano-Shushenskaya HPP using the body of mathematics of the three-dimensional nonlinear wave theory of earthquake resistance

Analyses are presented for verification of the earthquake resistance of a dam. __________ Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 4, April 2008, pp. 30–35.     

Another Look at Z-transform Technique for Deriving Unit Impulse Response Function

This paper presents a technique to derive the unit impulse response functions (UIRF) used for determination of unit hydrograph by employing the Z-transform technique to the response function derived from the Auto Regressive Moving Average (ARMA) process of order (p, q). The proposed approach was applied to reproduce direct surface runoff for single storm event data registered over four watersheds of area ranging from 0.42 to 295 km². It is observed that the UIRF based on ARMA (1, 2) and ARMA (2, 2) provides a better representation of the watershed response. Further, to test the superiority of the developed impulse response function form ARMA process, the direct runoff hydrographs were computed using the simple ARMA process and optimized Nash’s two parameter model and compared with the results obtained from UIRF’s of ARMA model. The performance of the models based on the graphical presentation as well as from the test statistics viz. RMSE and MAPE indicates that UIRF-ARMA (p, q) performs better than optimized Nash Model and mostly similar to simple ARMA (p,q) model. Further more, the ARMA process of order p ≤ 2 and q ≤ 2 is generally sufficient and less cumbersome than the Argand diagram based approach for UIRF derivation.     

Use of geophysical methods to assess the quality of compaction of fill soils

Quality of soil compaction in the Trans-polar regionis assessed by geophysical methods. __________ Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 3, March 2008, pp. 34–37.