Hill Reservoir Research Articles

Modélisation stochastique de l'usage agricole de l'eau et développement durable autour des lacs collinaires en Tunisie centrale : Application à la retenue de Djebel Hallouf dans le Gouvernorat de Kairouan

This research work attempts to determine and to analyse the behaviors of the farmers in term of adaptation and viabilily of production systems to the dubious and limited availability of water in small dams. For that, an analysis of the case of the Djebel Hallouf reservoir, located in the district of Kairouan with a storing capacity of 95 000 m 3 was used. The practical method followed in work consists of three essential stages : (i) initialy, a typology allowed the identification of the various production systems undertaken by farmers. The various types of exploitation around the reservoir were then modeled using the stochastic programming; (ii) in the second time, results of the basic models and their sensitivities to annuaI variations of irrigation water, were analyzed. The water demand functions of the various farms are set up and analyzed: (iii) in a third phase, and in order to analysis the technical and economic functioning of water reservoirs with regard to the problem of situation which affects its capacity in the time, dynamic model have integrated the factor time and have been useful to analysis the production systems evolution and their subsequent incomes. In general, the randomness of the filling of the reservoirs is the origin of the instability of the annual farmers incomes. The water demand functions of various farms are rigid owing to the fact that the cost of water represents a weak shore of the gross margin of crops. Production systems based on annual crops were not viable given the siltation process, which affects directly the through time water supply. The practice of these later comes in contradiction with the logic of sustainable development which governs the sectorial policy of the government in matter of hill reservoirs construction. Thus, the practice of tree plantation comes as a viable alternative able to generate through time relatively steady incomes and to induce consequently a sustainable local agricultural development around hill reservoirs.

Relationship between small dam efficiency and gully erodibility of the lithologic formations covering their watershed

Soil conservation strategy in the semi-arid areas of central Tunisia has focused on the construction of numerous hill reservoirs. However, limited rainfall combined with severe soil erosion is jeopardizing the usefulness of hill reservoirs such that there is an urgent need to undertake further studies into the location and efficiency of small dams. The paper reports investigations into the relationship between location of the dam and the underlying lithology of the catchment areas with the dam efficiency. A gully erodibility factor has been proposed for nine groups of lithological formations identified and a watershed lithologic number was computed as the product of seven watersheds for which 1:50,000 scale lithological maps were available. A significant linear relationship was determined between the watershed lithologic number and the efficiency of the small dams, indicating that an accurate lithological survey prior to small dam planning can be used to indicate the dam's likely efficiency and to plan any necessary soil and water conservation works in the catchment areas.

Initial Poststocking Mortality, Oxytetracycline Marking, and Year-Class Contribution of Black-Nosed Crappies Stocked into Tennessee Reservoirs

Initial poststocking mortality, oxytetracycline mark persistence, and year-class contribution were evaluated for black-nosed crappies, a morphological variant of the black crappie Pomoxis nigromaculatus, stocked into Tennessee reservoirs during 1997–1999. Average initial poststocking mortality was low (x = 13%, N = 44). Lake temperature and the difference between lake and hauling tank water temperatures were significant in explaining variability in arcsine-transformed mortality estimates; however, the variability explained by these factors was low (R2 = 0.15). Oxytetracycline immersion was a highly effective marking tool; 97–100% of all crappies treated were marked, and 99% of the marks were visible 36–110 weeks after marking. All control otoliths were correctly scored as unmarked during the evaluation, and mortality rates did not differ between marked and unmarked crappies. Year-class contribution was variable across reservoirs and was highest in Normandy Reservoir (34–93% at ages 1–3). Contribution at ages 1 and 2 was 11–24% in Woods Reservoir. Stocking did not supplement the crappie population in Lake Graham. Black-nosed crappies made up a significant portion (>50%) of the crappies harvested by anglers in Center Hill Reservoir 3 years after stocking was initiated. Conversely, black-nosed crappies made up a relatively small percentage (≤12%) of the crappies harvested in Cherokee Reservoir in the 4 years after initial stocking.

The origin of crude oils from the Shuguang-Huanxiling Buried Hills in the Liaohe Basin, China: evidence from chemical and isotopic compositions

Since the Shu103 well was successfully drilled in 1995, the Buried Hill reservoir is receiving a new exploration emphasis in the Liaohe Basin, China. The Buried Hill oils can be divided into 3 main types in the Shuguang-Huangxiling area based on their chemical and isotopic compositions. The first type is collected mostly from the Shuguang area. The similarity to the Es4 oils and the Es4 source rock extracts indicates that they were mainly expelled from the fourth member of the Shahejie formation (Es4) in the Chenjia Sag and/or Panshan Sag, deposited in a stratified paleolake system. The second is charactized by a relative high Pr/Ph ratio, low gammacerane content and depletion of 12C in individual n-alkanes. These characteristics represent a typical origin from dominantly freshwater paralic lacustrine sediments. Various biomarker indices of the other Buried Hill oils fall between the former two types. The authors infer that these oils may be derived from the adjacent Qingshui Sag and/or Panshan Sag, and were likely generated from transitional sedimentary facies between well-circulated freshwater paralic lacustrine and relatively closed saline lacustrine.

Groundwater geochemistry of a small reservoir catchment in Central Tunisia

Due to the scarcity of water resources in semiarid sedimentary basins, hill reservoirs are often constructed to recharge groundwater and limit runoff induced water loss. The impact of such reservoirs on groundwater chemistry is investigated in the aquifers of the El Gouazine watershed, Central Tunisia. Three groundwater types are recognised, Ca–HCO 3, Na–Cl and Ca–SO 4. The strong similarity between host rock and groundwater chemistries indicates significant rock–water interaction. A flowpath, along which the chemical composition of the groundwater evolves, can be identified using the contrast in stable isotope signature between upstream and downstream groundwater. Shallow upstream groundwater is recharged by the infiltration of rainwater with the rate of recharge strongly linked to the permeability of the host lithology. Calcium and HCO 3 are supplied to an alluvial aquifer from a more rapidly recharged limestone aquifer with the concentration of Ca and HCO 3 ions decreasing by dilution. The alluvial aquifer is also enriched in Ca and SO 4 during the downstream flow of groundwater through gypsiferous materials. There is evidence of mixing between meteoric groundwater and evaporated reservoir water. Below the reservoir and partly responsible for reservoir leakage is a sandy aquifer, formed by weathering and erosion of a sandstone host which also supplies water to the alluvial aquifer.

The HYDROMED model and its application to semi-arid Mediterranean catchments with hill reservoirs 2: Rainfall-runoff model applications to three Mediterranean hill reservoirs

Abstract. The objective of this work was to assess the performance of the newly developed HYDROMED model. Three catchments with hill reservoirs were selected. They are El-Gouazine and Kamech in Tunisia and Es Sindiany in Syria. The rainfall, the spillway flow and volume of water in the reservoirs were used as input to the model. Events that generated spillway flow were preferred for calibration. The results confirmed that the HYDROMED model is capable of reproducing the runoff volume at all the three sites. In calibrating single events, the model performance was high as measured by the Nash-Sutcliffe criterion for goodness of fit. In some events this value was as high as 98%. In simulation mode, the highest Nash-Sutcliffe criterion value was close to 70% in the El-Gouazine and Kamech catchments and close to 50% in the Es Sindiany catchment. Given the limited information available, especially on the unrecorded releases in the three catchments, the hydrological impact of site geology (e.g. Kamech), the unrecorded operator intervention during the spillway flow (e.g. Es Sindiany) and other unaccounted factors (e.g siltation, evaporation, etc.), these results are by and large very encouraging. However, they could be further improved as and when more information on the unrecorded parameters becomes available. Additionally, the results of this work highlighted the need for long term records with a large number of significant events that are able to generate spillway flow to obtain more consistent and reliable parameter values. It also highlights the need for more accurately recorded releases for irrigation and other uses. As these results are encouraging, more tests on those three and other sites are planned. Keywords: HYDROMED, rainfall-runoff model, Mediterranean, conceptual model

The HYDROMED model and its application to semi-arid Mediterranean catchments with hill reservoirs 3: Reservoir storage capacity and probability of failure model

Abstract. This paper addresses the issue of "what reservoir storage capacity is required to maintain a yield with a given probability of failure?". It is an important issue in terms of construction and cost. HYDROMED offers a solution based on the modified Gould probability matrix method. This method has the advantage of sampling all years data without reference to the sequence and is therefore particularly suitable for catchments with patchy data. In the HYDROMED model, the probability of failure is calculated on a monthly basis. The model has been applied to the El-Gouazine catchment in Tunisia using a long rainfall record from Kairouan together with the estimated Hortonian runoff, class A pan evaporation data and estimated abstraction data. Generally, the probability of failure differed from winter to summer. Generally, the probability of failure approaches zero when the reservoir capacity is 500,000 m3. The 25% probability of failure (75% success) is achieved with a reservoir capacity of 58,000 m3 in June and 95,000 m3 in January. The probability of failure for a 240,000 m3 capacity reservoir (closer to storage capacity of El-Gouazine 233,000 m3), is approximately 5% in November, December and January, 3% in March, and 1.1% in May and June. Consequently there is no high risk of El-Gouazine being unable to meet its requirements at a capacity of 233,000 m3. Subsequently the benefit, in terms of probability of failure, by increasing the reservoir volume of El-Gouazine to greater than the 250,000 m3 is not high. This is important for the design engineers and the funding organizations. However, the analysis is based on the existing water abstraction policy, absence of siltation rate data and on the assumption that the present climate will prevail during the lifetime of the reservoir. Should these conditions change, a new analysis should be carried out. Keywords: HYDROMED, reservoir, storage capacity, probability of failure, Mediterranean

Nested Species Subsets and Geographic Isolation: A Case Study

Insular systems tend to exhibit nonrandom patterns of species composition in which smaller species assemblages contain successive subsets of those found on richer ones. The fact that such nested patterns of species composition have usually been observed in systems where species number is correlated with island size has led to the hypothesis that differences among species in the effect of island size on the probability of extinction represent the main mechanism producing nested patterns of species composition. This study tested the hypothesis that differences among species in dispersal ability may interact with geographic isolation to produce nested subsets of species composition. This hypothesis was tested in a systems of woody plants inhibiting artificial islands that were created by the filling of the Clarks Hill Reservoir, Georgia, USA. All of the studied islands had been logged prior to their separation from the mainland and their species number 34 yr later was found to be negatively correlated with distance to the closest mainland. The results of the present analysis indicated that (1) species occupancy of the whole island system was highly nested, (2) nestedness occurred with respect to geographic isolation but not with respect to island size, (3) only a small portion of the overall species included in the study contributed to the observed nestedness, and (4) the degree to which individual species contributed to the observed nestedness was correlated with their dispersal properties, with wind—dispersed species showing no evidence for nestedness and species lacking adaptations for long—range dispersal showing the strongest patterns of nestedness. These results indicate that isolation effects may interact with species—specific dispersal properties to produce nested subsets of species composition.

Effects of isolation, logging and dispersal on woody-species richness of islands

Isolation effects on species richness of woody plants were investigated in a system of islands that were created by the filling of the Clarks Hill Reservoir, Georgia. This reservoir was built between 1946–1954. Some islands were logged and cleared of woody plants prior to the filling of the reservoir and others were not logged. The presence of logged versus unlogged islands in the same system allowed us to test whether and how geographical isolation interacts with island history and species-specific dispersal properties in determining patterns of among-island variation in species number. Thirty-six years after the islands were created, logged islands had significantly fewer species of woody plants than unlogged ones. On logged islands, total number of woody species was negatively correlated with distance to the closest mainland (r=−0.95). On unlogged islands, variation in species number was very low (CV=4.9%) and was not correlated with distance to the mainland. These results indicate that the studied system as a whole has not yet reached equilibrium. However, the mean number of species on unlogged islands was very close to the intercept of the regression obtained for logged islands, suggesting that islands close to the mainland have already reached their equilibrium species richness. This conclusion is consistent with predictions of island biogeography theory. When species representing different dispersal properties were analyzed separately, statistically significant distance effects were obtained for bird-dispersed species (r=0.88) and for species with no adaptations to bird or wind dispersal (r=0.81). Wind-dispersed species did not show a decrease in species number with increasing isolation, but their relative frequency was positively and significantly correlated with distance to the mainland (r=0.94). Historical factors, as well as differences among species in dispersal properties, are important in explaining patterns of among-island variation in species number.

Inter-reservoir interactions: Effects of a new reservoir on organic matter production and processing in a multiple-impoundment series

Impoundment of the R.B. Russell Reservoir (RBR) between two existing reservoirs (Hartwell Reservoir (HT) upstream and Clark Hill Reservoir (CH) downstream) on the Savannah River (Georgia-South Carolina, USA) provided an opportunity to investigate the limnological influence of interreservoir transfers of nutrients and organic matter down a multiple-impoundment series. The objective was to document within- and among-reservoir patterns in organic matter production and processing in the HT-RBR-CH reservoir series as organic matter dynamics were influenced by the inundation and subsequent stabilization of the RBR basin.

Habitat Preferences, Survival, Growth, Foods, and Harvests of Walleyes and Walleye × Sanger Hybrids

We compared habitat preferences, survival, growth, foods, and harvests of stocked walleyes Stizostedion vitreum and walleye ♀ × sauger S. canadense ♂ hybrids in Pleasant Hill Reservoir, Ohio. Both fishes were stocked at similar rates and sizes (about 40 mm mean total length) in late May or early June 1979–1982. Neither group showed consistently better survival. Growth was similar until age 2. Thereafter, hybrids grew faster than walleyes. Age-0 walleyes occurred mostly over fine substrates in early summer and coarse substrates by fall. Habitat selection by age-0 hybrids was similar to that of walleyes, except hybrids preferred finer substrates in fall. Older hybrids and walleyes moved offshore at temperatures above 22°C. Diets of both fishes were similar, but hybrids ate more littoral fishes, whereas walleyes ate more pelagic fishes. Age-1 and older hybrids and walleyes ate mostly invertebrates in spring. Age-0 gizzard shad Dorosoma cepedianum were the most important prey for all ages of both groups. Hybrids and walleyes were caught by anglers in proportion to their abundances and contributed most to the fishery at ages 1 and 2. Hybrids have the potential to breed with either parent species and may introduce new genetic material into existing walleye or sauger populations. Data from our study and other Ohio waters show that hybrids can support important fisheries, particularly in tailwaters, and may be more successful than walleyes in impoundments with short water-retention times.

The nature of zooplankton spatial heterogeneity in a nonriverine impoundment

Knowledge of spatial heterogeneity characteristic of reservoir plankton communities is fundamental to a variety of ecological studies. Degree of spatial heterogeneity in the zooplankton community of Center Hill Reservoir, with water residence times of 50–250 days, was positively correlated with rate of water influx. Important spatial differences resulted from the contrast between zooplankton associated with new and longer-impounded water. The nature of spatial heterogeneity differed fundamentally from the more riverine impoundments where spatial differences are often persistent and characterized by gradual change (as opposed to contrast) in plankton assemblages with respect to location. Magnitude of plankton spatial heterogeneity in nonriverine impoundments may be predictable from inflow rates. Areas, between which major differences in plankton communities exist, may also be definable from knowledge of inflow dispersal patterns in these impoundments.

Cross‐hole seismic surveys: Applications for studying subsurface fracture systems at a hot dry rock geothermal site

The use of cross hole seismic surveys for delineating the location and size of subsurface fracture systems is investigated. The radiation pattern for P and S waves emitted by a seismic source in a borehole is derived. Experimental work in relatively homogeneous granite suggests that the derived relationship adequately describes the radiation pattern for both explosive sources and acoustic transducers placed in fluid‐filled boreholes. Using the above functional expressions for the S‐ and P‐wave amplitudes, we have developed a technique to estimate Q and locate discrete fractures in crystalline rock that compose the Hot Dry Rock Geothermal Reservoir at Fenton Hill, New Mexico. To calculate Q, we measure the P‐ and S‐wave amplitudes as a function of distance from the source, compensate for the radiation pattern and geometrical spreading effects, and match the relative attenuation to a function of the form [Formula: see text] using a least‐squares regression technique. For undisturbed parts of the reservoir, we obtain values of Q on the order of 160 for P waves and from 170 to 150 for S waves. Using our method we are able to detect a decrease in the average Q due to extensive fracturing following heat extraction from the Fenton Hill reservoir. We have also been able to locate discrete large‐scale fractures in the reservoir by noting regions characterized by a sudden change in signal amplitude, wave form or frequency content that cannot be explained by radiation pattern effects or increases in source‐receiver separation. These localized attenuating regions in the Fenton Hill Hot Dry Rock reservoir are probably open fractures.

Changes in phosphoadenylate concentrations and adenylate energy charge as an integrated biochemical measure of stress in invertebrates: The effects of cadmium on the freshwater clamCorbicula fluminea

Concentrations of phosphadenylates ATP, ADP and AMP were measured in foot muscle tissue of the Asian clam, Corbicula fluminea Muller, by the luciferin‐luciferase bioluminescence technique. Total adenylate concentration μM · g‐ 1, dry weight and adenylate energy charge [AEC = (ATP+1/2ADP)/(ATP + ADP + AMP] were calculated. The effects of laboratory acclimation, starvation and exposure to 0.005, 0.05, 0.5 and 5.0mgCd · l‐1 were investigated. We observed no significant difference between the AEC of clams collected from the Savannah River Channel below Augusta, Georgia and those collected from Clark Hill reservoir on the Savannah River above Augusta. When C. fluminea, collected from the Savannah River were taken to the laboratory and fed and maintained in aerated water at 21°C, the AEC increased from 0.76±0.06 to 0.95±0.01 (x±95% CI, n = 8). This indicates that C. fluminea in the Savannah River were living under sub‐optimal conditions. Starvation for 10 and 20 days did not significantly decrease the AEC. Howe...

SPATIAL VARIATIONS IN ABUNDANCE OF PHYTOPLANKTON, ZOOPLANKTON, AND LARVAL FISHES IN CENTER HILL RESERVOIR

Densities of phytoplankton, zooplankton, and larval fishes in Center Hill Reservoir, Tennessee, USA, were determined to evaluate differences in abundance between embayments and mainstream areas and to assess longitudinal gradients in the reservoir. Plankton were collected monthly from May 1978 through June 1979 and larval fishes were collected biweekly from May through August 1978 at five mainstream and five embayment sites established along the reservoir.Statistical analyses for the majority of plankton and larval fishes indicated that spatial variations in abundance were primarily related to localized environmental conditions rather than the hydraulic gradient of the reservoir. Most taxa were more abundant in embayments than in nearby mainstream sites, and although abundance usually varied significantly among the five mainstream stations, densities showed no consistent gradient in the up stream-downstream dimension of the reservoir. Abundance of phytoplankton and rotifers was more uniform at the mainstream stations during periods of low inflow and high water temperature. Copepod and cladoceran densities, however, were more uniform during periods of high inflow. The existence of spatial variations in biological communities should be recognized when assessing trophic status or developing predictive models of reservoir systems.

Hypolimnial oxygen injection: a benefit to downstream fish populations?

Changes in electrofishing catch rates downstream from Clark Hill Reservoir were only mildly affected by addition of oxygen to the hypolimnion waters prior to discharge in spite of increases in oxygen concentration. Changes in abundance and distribution of six major species were detectable and beneficial effects undoubtedly occur, but the overall benefit of oxygenation, at least at Clark Hill Dam, is questionable. At other dams with a more pronounced and prolonged oxygen-poor period, oxygenation may be worthwhile.

Microearthquake spectra in the southeastern United States

abstractDisplacement spectra from microearthquakes in the Clark Hill Reservoir Area and the Jocassee Reservoir Area, both in the Piedmont Crystalline Province, showed similar spectral properties typified by a sharp spectral corner, ω-cubic, high-frequency decay and ratios of P- and S-wave corner frequencies predominantly greater than unity. Displacement spectra from microearthquakes in the Maryville Tennessee Area in the Folded Appalachian Province showed transitional spectral corners, ω-square or less high-frequency decay and a ratio of P- to S-wave corner frequencies less than or equal to unity. These spectral characteristics are interpreted as evidence for a possible regional variation in the earthquake mechanism. The Clark Hill and Jocassee spectral characteristics are best explained by an earthquake mechanism typical of an equidimensional fault which nucleates rupture at a point of high resistance to slip and ruptures at a velocity greater than the S-wave velocity along an existing fracture. The Maryville spectral characteristics are best explained by rupture at velocities less than the S-wave velocity along faults which may show premature arrest of movement.

Chromium levels in fish from a lake chronically contaminated with chromates from cooling towers† ‡

Chromium concentrations of several fish species [bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides) goldfish (Carassius auratus), and mosquitofish (Gambusia affinis)] from White Oak Lake (WOL), a small impoundment which formerly received cooling water blowdown containing high Cr(VI) concentrations, were measured to determine levels of tissue accumulation. Chromium concentrations in the muscle and/or whole body (excluding G.I. tract) of some species in some years were found to be negatively correlated with total fish weight. Results suggest that Cr levels in muscle and whole body of most species analyzed from WOL and from Melton Hill Reservoir, an uncontaminated impoundment, may be inversely related to fish weight. Muscle and wholebody Cr concentrations were not significantly different from each other in bluegill or largemouth bass. With the exception of goldfish collected in 1969, between species comparisons of chromium levels in WOL fish within years showed no statistically significant differences, indicating that there was not trophic level effect on Cr accumulation in tissues of the species examined. There was also no signiticant aitterence in Cr concentration in muscle of bluegill and largemouth bass from WOL and Melton Hill Reservoir, indicating that these species either effectively regulate their Cr absorption or that the elevated Cr levels in WOL were in a form that is unavailable for absorption into tissues.

Earthquakes associated with the Clark hill reservoir, South Carolina-a case of induced seismicity : Talwani, P Engng Geol, V10, N2–4, Dec 1976, P239–253

Earthquakes associated with the Clark hill reservoir, South Carolina-a case of induced seismicity : Talwani, P Engng Geol, V10, N2–4, Dec 1976, P239–253

Earthquakes associated with the Clark Hill reservoir, South Carolina — A case of induced seismicity

Following the McCormick County, South Carolina, local magnitude 4.3 earthquake on August 2, 1974, continuous seismic activity has been observed in the area. The epicenters are located within 3 km from the Clark Hill reservoir. The shallow seismic activity appears to be related to water level fluctuations in the reservoir, and follows them by about two days. The frequency of earthquakes is related to the rate of change of water level, while the energy release is seen to depend on the water level itself. Pore pressure fluctuations at focal depths in a regime of high tectonic stresses is the suggested cause for the triggering of earthquakes.