Turbid Streams Research Articles

Assessing flash flood erosion following storm Daniel in Libya

The eastern Mediterranean basin is witnessing increased storm activity impacting populous urban coastal areas that historically were not prone to catastrophic flooding. In the fall of 2023, Storm Daniel struck the eastern coast of Libya, causing unprecedented flash floods with a tragic death toll and large-scale infrastructure damages. We use Sentinel-1A C-band SAR images to characterize the resulting flash flood erosion and sediment load dynamics across the watersheds and to map damages within coastal cities at their outlets. Our results suggest that sediment loading, resulting from surface erosion, increased the density of turbid streams. The above exacerbated the catastrophic impact of the flash floods in the coastal cities of Derna and Susah, where 66% and 48% of their respective urban surface have experienced moderate-to-high damages. Our findings highlight the increased vulnerability of coastal watersheds in arid areas within the eastern Mediterranean basin due to the forecasted increase in hydroclimatic extremes and call for a transformative coastal management approach to urgently implement nature-based solutions and land-use changes to mitigate these rising risks.

Male guppies compensate for lost time when mating in turbid water

Turbidity (a measure of the cloudiness of water) decreases the visual range of organisms, altering interactions within and between species. For species that visually assess mates, turbidity may affect mating interactions and mate choice. A central question, then, is to what degree organisms plastically adjust mating behaviors to cope with visually altered environments. Here, we investigate the effect of turbidity on the mating behavior of guppies (Poecilia reticulata) in Trinidad, where some streams are increasingly turbid due to upstream rock quarrying. We collected fish from two highly turbid streams (with upstream rock quarries) and two pristine streams (no upstream quarries) in the same drainages. We then observed male mating behaviors with females from the same populations in both turbid and clear assays, recording displays and sneak copulation attempts. Males from turbid streams showed greater individual consistency in mating behaviors. But regardless of provenance, male guppies spent less time associating with females in turbid water overall. When males and females did interact, however, males greatly increased the rate of all mating behaviors in turbid as compared to clear water. Thus, even when lacking a long-term evolutionary history with high turbidity, guppies compensate for lost time when mating in a visually altered environment. Given the global nature of increases in turbidity, understanding behavioral responses to this aquatic anthropogenic change is critical. Here, we investigate the degree to which Trinidadian guppy males in affected areas are able to plastically compensate in turbid water by adjusting mating behaviors. We also test the degree to which previous chronic exposure to turbidity alters this plasticity. In contrast to predictions, we did not find population differences in plasticity; across all populations, however, we found significant plasticity in the guppy mating system in response to anthropogenically increased turbidity. While males spent less time associating with females in turbid water overall, males increased mating effort during periods of association, compensating for lost time in turbid water. We discuss this plasticity and the implications for guppy sexual selection and secondary sexual characteristics such as coloration.

Evaluating the capabilities of the CASI hyperspectral imaging system and Aquarius bathymetric LiDAR for measuring channel morphology in two distinct river environments

AbstractRemote sensing is a powerful tool for examining river morphology. This study used detailed field surveys to assess the capability of the CASI hyperspectral imaging system and Aquarius bathymetric LiDAR to measure bed elevations in rivers with disparate optical characteristics. Field measurements of water column optical properties in the clear Snake River, the more complex Blue and Colorado, and highly turbid Muddy Creek were used to calculate depth retrieval precision and dynamic range. Differences in depth of a few centimeters were detectable via passive optical techniques in the clearest stream, but precision was greatly reduced under turbid conditions. The bathymetric LiDAR evaluated in this study could not detect shallow depths or differences in depth smaller than 11 cm owing to the difficulty of distinguishing water surface and bottom returns in laser waveforms. In clear water and with high radiometric resolution, hyperspectral systems such as CASI could detect depths approaching 10 m, but semi‐empirical analysis of the Aquarius LiDAR indicated that maximum detectable depths were of the order of 2–3 m in the clear‐flowing Snake River, and closer to 1 m in the more turbid streams. Turbidity also constrained spectrally based depth retrieval, and depth estimates from the Blue/Colorado were far less reliable than on the Snake. Both sensors yielded positively biased (0.03 m for CASI, 0.08 m for Aquarius) bed elevations on the Snake, with precisions of 0.16–0.17 m. For the Blue/Colorado, mean errors were of the order of 0.2 m, biased shallow for optical data and biased deep for LiDAR, although no Aquarius laser returns were recorded from the deepest parts of these channels; precisions were reduced to 0.29–0.32 m. Both approaches have advantages and limitations, and prospective users must understand the capabilities and constraints associated with various types of remote sensing to ensure efficient use of these evolving technologies. Copyright © 2015 John Wiley & Sons, Ltd.

Sapphire Fiber Evanescent Wave Absorption in Turbid Media

The influence of particulates on sapphire fiber evanescent wave absorption by water has been studied. Suspensions containing micro-sized graphite flakes and glassy carbon powder were used. Conventional free-space transmittance measurements of these samples showed strong absorption and scattering, which severely screened the absorption by water. However, the absorption on the water band determined from the evanescent wave interaction was unaffected by the presence of the graphite flakes. These results indicate that fiber-optic evanescent wave chemical sensors may be suitable for process control applications involving turbid reactor streams.

An Assessment of Deadhead Logs and Large Woody Debris Using Side Scan Sonar and Field Surveys in Streams of Southwest Georgia

AbstractLarge woody debris provides essential habitat in sand‐bed streams of the southeastern United States. In many Coastal Plain streams, pre‐cut timber, lost more than a century ago during river transport, contributes to the extant large woody debris pool. The extraction of these logs, otherwise known as deadhead logging, threatens habitat integrity in these systems. Little is known of the distribution, abundance, and ecological value of deadhead logs, thus hindering attempts to manage and protect this resource. Moreover, the use of traditional field‐based methods to inventory wood is slow and costly in large turbid streams. Our objectives were to assess wood at several sites in southwest Georgia using traditional methods, then use these data to evaluate the efficacy of quantifying wood using side scan sonar imagery. Deadhead logs were widely distributed and constituted a substantial proportion (> 50% volume and surface area) of the total large woody debris found at study sites. Given these findings, the wholesale removal of deadhead logs could largely impact the ecological integrity of such streams. Analyses revealed strong correlations (r2 = 0.82—0.98) between sonar wood estimates and actual counts suggesting that side scan sonar can be used as a rapid, inexpensive method to quantify wood throughout navigable systems.

Threatened fishes of the world: Silurus aristotelis (Agassiz 1856) (Siluridae)

Common names: Aristotle’s catfish (E), glanidi (G), Aristotelis derived from the ancient Greek philosopher Aristotle (384 – 322 BCE) who was the first described the reproductive strategy and parental care of the species. Conservation status: Listed as endangered in the EU Habitat Directive 92/43/EEC (Annexes II, IV). Strictly protected by the Bern Convention (Appendix II). Protected by Presidential Decree No. 67/1981 of the Greek State. Identification:D 3, A 73 (70 – 74), C 17, P l, 12 (10 – 13), V 10 Vertebrae 56. The hard ray of the pectoral fin has 12 – 14 serrations, males have wider ray with more serrations than females. Body elongate, cylindrical anteriorly, compressed posteriorly, males are more slender than females. Head large and depressed, two pairs of barbells, one in each maxilla, the maxillary pair are especially long. Gape very wide, the lower maxilla is prolonged. The dorsal fin is very small, caudal fin is distinct from the anal fin, anal fin-base very long. Colouration variable; usually fairly dark, the upper side dark brown olive-green to blue-black and the flanks paler. Underside, especially the belly, pale to white. Upon this ground colour are imposed cloudy or spotted marblings. The skin is scaleless, max TL=40 cm, maximum age 10 years. Distribution: Endemic to the lower Acheloos River system (W Greece) which includes the lakes Trichonis, Lysimachia, Ozeros, Amvrakia. Two nonnative populations where established by translocation of fish from Trichonis Lake to Pamvotis Lake (NW Greece) and Volvi Lake (N Greece) between 1950 and 1955 (Leonardos 1996). Abundance: Was originally abundant in the distribution area. In recent years most populations exhibit tendencies to decline due to high mortalities occurring from the pollution and fishing pressure. Healthy populations in the Lysimachia and Pamvotis Lakes, small populations in Trichonis and Amvrakia Lakes, and very rare in Volvi Lake. Habitat and Ecology: Occurs in the slow flowing reaches of rivers with turbid water, streams and canals, in lakes especially with dense weed-bed and muddy bottoms. It feeds at night predominantly on fish live and dead, and secondarily on crustaceans, gastropods, aquatic insects, small frogs and snakes (lliadou & Ondrias 1986). Reproduction: Females mature at 2 – 3 year, extended breeding period with ripe gonads from April to July (lliadou & Ondrias 1986). Eggs are laid near the shore in nest-building with pieces of aquatic plants, part of woods. Artificially fertilized eggs have diameter around 2.7 mm, and hatch after 5 days at 23 C. The newly hatched larvae have 7 mm NL (Economou et al.1994). Threats: Major threats are connected with habitat loss or degradation caused by human activities. The main threats are habitat degradation (Pamvotis Lake, Volvi Lake), runoffs from agricultural (Amvrakia, Ozeros, Lysimachia), municipal effluences (Lysimachia and Pamvotis Lakes), water level fluctuations (Amvrakia, Pamvotis). Over fishing and use of illegal fishing methods is widely practiced in Trichonis Lake. Conservation action: At present, no actions are implemented for the conservation of the species. Conservation recommendations: Pollution from agricultural and sewage effluent should be reduced. The ecology and life traits of S. aristotelis need to be further studied so as to quantify the impact of habitat loss and fragmentation on its survival. The reproductive biology and the artificial reproduction of the fish must be studied with an emphasis in reintroduction programs wherever the species is extinct or rare. Remarks: Genetic (mitochondrial and microsatellite DNA) analyses revealed the clear differentiation of the native Trichonis and Amvrakia populations. (Triantafyllidis et al. 2002). Consequently, populations should be managed and conserved separately. Enhancement stockings, with translocations of individuals from one site to another, are not recommended. Although the introduction of S. aristotelis in the Lake Volvi is considered successful based on genetic (microsatellite) variability estimates (Triantafyllidis et al. 2002).

An Electric Trawl for Sampling Bottom-Dwelling Fishes in Deep Turbid Streams

Abstract A steel-framed trawl 61 cm deep × 183 cm wide was constructed that can be towed from the front of a conventional DC electrofishing boat. Both trawl and boat functioned as cathodes; a 28-cm-diameter sphere served as the anode, This unit effectively sampled bottom-dwelling fishes such as channel catfish Ictalurus punctatus in water too deep (3–7 m) to sample with conventional electrofishing gear and too turbid for making scuba observations. The trawl catch complemented the catch of fishes that exhibited galvanotaxis and could be dipnetted at the anode.

Attraction of Notropis lutrensis (Cyprinidae) to Water Conditioned by the Presence of Conspecifics

Responses of red shiners, Notropis lutrensis, to water conditioned by the presence of conspecifics were evaluated in laboratory preference chambers. Fish from the South Canadian River (Arkansas River drainage) and Lake Texoma (Red River drainage), tested under different conditions at different times of year, all exhibited a strong attraction to water previously occupied by conspecifics. Olfaction as a cue to habitat selection is discussed with respect to the known ecology of the species. Some fishes of the turbid streams of the Great Plains have highly developed olfactory senses (Moore 1950). Notropis lutrensis (red shiner), one of the most abundant Great Plains species, can use physico-chemical and auditory stimuli in selecting habitat or locating mates (Delco 1960, Matthews and Hill 1979), but its response to olfactory stimuli has not been reported previously. Our field studies in the South Canadian River near Norman, Oklahoma, suggested that odor might also provide this species a cue to habitat selection, resulting in their attraction to water preconditioned by the presence of conspecifics. In October 1976, we collected 19,182 N. Iutrensis in a ca. 600 m section of the South Canadian River. Of those, 90.7% were taken in two backwater pools (each ca. 20 x 5 m) located near the main river channel (Matthews and Hill 1979). In addition to these collections, repeated visits to the site indicated use of the backwaters by large numbers of red shiners throughout October. We hypothesized that the shiners concentrated in the backwaters, despite adequate water for greater dispersal, because those areas presented favorable physico-chemical conditions. The backwaters were relatively stable thermally, fluctuating 1-2?C daily, compared to fluctuation of up to 12?C daily at mainstream locations. Additionally, diurnal pH in the backwaters (8.2-8.5) was closest to the pH selected by N. lutrensis in the laboratory (Matthews and Hill 1979), and pH in the mainstream (8.7-9.5) approached values stressful to this species (Matthews and Hill 1977). During the day, sharp temperature and pH gradients, which shiners could have used as habitat cues, existed between the mainstream and backwaters. At night, by contrast, no marked gradients existed, yet the thousands of N. lutrensis remained in the backwaters, not dispersing into nearby standing-water pools of the river mainstream. This behavior suggested that some factor not detected by our measurements, e.g., conditioning of backwaters by the presence of conspecifics, played a role in habitat selection by the species. The crowding of thousands of individuals into small pools undoubtedly resulted in accumulation of odors of mucous, excretory products, or other exudates. The attraction of fishes to water having the odor of conspecifics is well documented (Kleerekoper 1969, Fine et al. 1977).

Uncertainty in dissolved oxygen prediction due to variability in algal photosynthesis

The contribution of variance in river community metabolism to overall uncertainty in predictions from dissolved oxygen models is evaluated using Monte Carlo simulation. Results using a modification of the Streeter-Phelps model to include a term for mean daily net production show that uncertainty in parameters used to describe community metabolism must be considered when probability distributions of dissolved oxygen in rivers are estimated. This conclusion is shown to be valid for a range of conditions and is therefore applicable to all but heavily polluted or highly turbid streams. Use of a refined version of the oxygen balance equation that accounts for diel variation in algal productivity demonstrates that variance in dissolved oxygen in rivers is likely to be much larger than that predicted by models that use mean daily values of net production.

The Public Water Supplies of Montana

When Montana was carved out of the Louisiana Purchase in 1864, it was made the third largest state in the Union. Stretching approximately from 104° to 116° west longitude it is 550 miles from east to west. From the south boundary at parallel 45° to the Canadian line on the north at parallel 49° it is 280 miles wide. Such a large area embraces a wide range of soil characteristics, topography and natural resources. It is difficult to present all these in such a brief description as this paper pretends to give, but there are certain natural divisions which will be used to give as clear a picture of the situation as is possible. This is the Land of the Shining Mountains and it is here that one first approaches the mighty peaks of the Rockies when traveling westward from the plains on the northern routes. The continental runs in a northwest-southeast direction through the western part of the state effectively cutting it into two natural divisions. By far the larger of these lies to the east stretching to the plains. The western portion is all mountainous with the characteristic valleys nestling among the many ranges. From the standpoint of public water supply it is convenient to consider the state in this way for there are certain characteristics common to each portion. Table 1 shows the result of such a division. On the west side of the divide the public supplies are taken largely from streams and springs. Relatively few wells are used. On the eastern side, however, especially away from the mountains, there are more wells, showing the attempt to avoid the necessity of purifying the more turbid streams, even though it means the use of water of high' chemical content in many cases.