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Salamanders are critical components of forest ecosystems, in terms of total biomass, as well as for their value as indicators of ecosystem stress. Considering the worldwide decline in amphibian populations, the known effects of timber harvest on salamander populations, and the importance of the forest products industry in Kentucky and elsewhere, the impacts of silvicultural operations on salamander communities cannot be overlooked. The objective was to investigate the effects of three different silvicultural treatments, each involving different streamside management zone (SMZ) characteristics, on salamander communities in ephemeral streams. Data were collected by regular checks of pitfall traps, coverboards, and transect searches. Using both pre- and post-harvest data, abundance estimates were acquired using binomial mixture models. Declines in some species of terrestrial and stream-breeding salamanders were detected, and were shown to be likely related to characteristics of the corresponding silvicultural treatment. Applying modest SMZ regulations to ephemeral streams would likely alleviate these declines significantly.

Mercury (Hg) transport in streams is typically facilitated by dissolved organic matter (DOM), however, the dynamics of Hg and DOM during snowmelt in montane watersheds are poorly understood. Hg transport during snowmelt is widely recognized as a significant source of Hg to downstream lakes and reservoirs, such as Jordanelle Reservoir where fish consumption advisories are in effect due to elevated Hg concentrations in certain species of fish. For this study, total mercury (THg), methylmercury (MeHg), and DOM samples were collected at three sites in the upper Provo River, northern Utah, during the 2016 and 2017 water years. To evaluate Hg and DOM sources, samples were collected from snowpack and ephemeral streams in the watershed. In-situ fluorescent DOM (fDOM) data and other parameters were measured in the river to characterize high-frequency variation in water chemistry. Excitation-emissions matrices (EEMs) were used to determine changes in DOM characteristics during snowmelt. Hg concentrations increased in the upper Provo River from /L during baseflow to >;7 ng/L during the snowmelt period (~April-July), with filtered THg concentrations approximately ~75% of the unfiltered concentrations. In the watershed, filtered THg concentrations ranged from ~0.4 ng/L in snowpack to ~8 ng/L in ephemeral streams. Annual THg loading from the Provo River to Jordanelle Reservoir was approximately 1 kg/yr with ~90% of the flux occurring during the snowmelt period. High correlations between filtered THg and fDOM allowed for the development of a high frequency filtered THg proxy using in-situ fDOM sensors. DOM characteristic during the snowmelt period showed that Hg transport was facilitated by humic substances which was sourced from upland soils. Fractions of filtered methylmercury (MeHg) and filtered THg (filtered MeHG:filtered THg) were ~0.1 during baseflow and reduced to ~0.01 during snowmelt, implying that snowmelt runoff has little impact on the MeHg flux to Jordanelle Reservoir. The results suggest that Hg and DOM are flushed from soils during snowmelt, and that a significant majority of the Hg flux occurs the snowmelt period. Our study has implications for understanding Hg sources and transport mechanisms in other snowmelt dominated watersheds.

Boreal landscapes cover a large part of both Sweden and the northern hemisphere. The hydrology of the boreal landscape is complex, with several factors that can affect it in a physical and/or chemical manner. In the Krycklan catchment area, 68km2, located in northern Sweden close to Umeå, data has been collected at several sites giving both stream flow and water chemistry information. In 2017 samples from 34 sites were collected and analysed from ephemeral streams within the Krycklan catchment area for the first time ever.  In this project, data that has been collected from the ephemeral streams will be correlated with data from the perennial streams in the catchment area. There are several hypotheses at the start of this project that suggests that within the ephemeral streams the DOC will be lower, and the CO2 will be the same. The aim of the project is to find out if there are any patterns that differentiates the ephemeral streams from the perennial streams or if there are no patterns at all. Since there is not so much data available for the ephemeral streams, the conclusions that might be reached in this project won’t be completely reliable. However, if interesting patterns are found the project could expand in the future and more samples can be taken to use for more precise analyses. / Boreala landskap täcker en stor del av både Sverige och norra halvklotet. Det boreala landskapets hydrologi är komplext, med flera faktorer som kan påverka det på ett fysiskt och/eller kemiskt vis. I Krycklans avrinningsområde, 68 km2, beläget i norra Sverige nära Umeå, har data samlats in på flera platser som erbjuder data för både flöde och vattenkemi. År 2017 samlades prover från 34 efemära strömmar och analyserades för första gången inom Krycklans avrinningsområde. I det här projektet kommer data som samlats från de efemära strömmarna att korreleras med data från de konstanta vattendragen i avrinningsområdet. Det finns ett par hypoteser i början av detta projekt som tyder på att inom de efemära strömmarna kan DOC halter vara lägre och CO2 halter kommer att vara densamma. Syftet med projektet är att ta reda på om det finns några anmärkningsvärda skillnader mellan de efemära strömmarna och de konstanta vattendragen. Eftersom det inte finns så mycket data tillgänglig för de efemära strömmarna kommer de slutsatser som kan uppnås i detta projekt inte att vara helt tillförlitliga. Om intressanta mönster finns däremot kan projektet expandera i framtiden och fler prover kan tas för att användas för mer exakta analyser.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / A critique of statistical properties of monthly flows on an ephemeral stream in Arizona is given. A subjective procedure, justified for managerial purposes not concerned with the variability of flow within the month, is proposed for sequential generation of monthly flow data. Ephemeral flows should be modeled by starting with at least historical daily flows for more meaningful monthly flow models. Stochastic properties of monthly streamflows and state transition probabilities are reviewed with regard to ephemeral streams. A flow chart for a streamflow model geared to digital computers, with a simulation of streamflow subroutine, is developed. Meaningful monthly flow models could serve as a check on alternative models (subjective matrix, lag-one auto regressive, harmonic, bivariate normal, bivariate log-normal models). Rules and guidelines are presented in developing meaningful probability matrices.

From the Proceedings of the 1978 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 14-15, 1978, Flagstaff, Arizona / Discontinuous water quality data for the San Pedro River in southeastern Arizona is analyzed to illustrate the nature of water quality problems of ephemeral flow. The San Pedro drains a northerly-trending basin of 4,483 square miles, of which 696 are in Mexico and 3,787 in Arizona. Several questions arise in the consideration of a rational management plan: what is the necessity for protection of ephemeral flow quality when the channel consists of a dry wash much of the year, where there is little aquatic or wildlife to protect, and where occasional flow during flood conditions is put to little use by humans; and where and how do we use the ephemeral flow it is indeed decided to utilize it. Such questions as these form the basis of this discussion in an effort to bring out the point that water quality problems of ephemeral flow in arid areas differ from those in the humid zone. It is argued that in between the extremes of prohibiting or treating all runoff or eliminating all sources of pollution, there is actually little that can be done to control all sources of pollution in this typical arid stream, despite the fact that standards, for the most part unattainable, have been set for this flow.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / In order to construct a simulation model for ephemeral streamflow and to examine in depth the problem of the worth of data for that model, measurements of the ephemeral streamflow of Rillitto creek, Tucson, were analyzed for the period 1933-1965. The simulation model was based on several hypotheses: (1) flow durations and their succeeding dry periods (time when no flow is present) are independent; (2) the distribution of the lengths of the dry periods and flows is stationary over a certain period of the year (summer); (3) stationary probability distributions for flow durations and for dry period lengths can be derived. A related problem was how to derive a simulation model for the total amount of flow (in acre-ft) within 1 flow period. Three variables were considered: flow duration (minutes), peak intensity of flow (cu ft/sec) and antecedent dry period-minutes (ADP). Because the assumption of variance constancy does not hold, a multiplicative regression model was used. Using an analysis of variance, which is described in detail, the worth of the 3 kinds of data were examined in relation to total flow. It was concluded that there are at least 5 times during the year when the flow intervals differ significantly, and the ADP is not important in determining flow volume because of the poison flow arrival rate in summer. Events occur at random and are not clustered as in summer, indicating that channel moisture does not differ much between flow events.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / A preliminary study was made with the objective of examining nitrogen species transformations of treated sewage effluent releases within the channel of an ephemeral stream, the Santa Cruz River of southern Arizona. Water quality samples were taken at established locations in sequence so that peak daily flows could be traced as the effluent moved downstream. Results indicate that increased nitrification, coinciding with changing stream characteristics, starts in the vicinity of Cortaro Road (6.3 river miles from the Tucson Sewage Treatment Plant discharge). Through physical-chemical changes in streamflow, nitrate -nitrogen values reach a maximum at approximately 90-95 percent and 60-80 percent of total flow distance for low flows and high flows, respectively. Concentrations of ammonia-nitrogen and total nitrogen decrease continuously downstream with both high and low flows. Therefore, the rate of nitrification within sewage effluent releases in a desert stream channel evidently is related to flow distance and physical characteristics of the stream.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / An average of 6 to 13 streamflows from intense summer convective storms occurs annually in the walnut gulch experimental station, 58 square miles in southeastern Arizona. Flows last generally less than 6 hours, and the channels are dry 99 percent of the time. The limiting factors imposed by the geology and geomorphology of the channel to transmission losses of a 6 square mile channel in the station are described. The Precambrian to quaternary geology is outlined, and geomorphology of the channels are described. Volume, porosity and specific yield of alluvium were determined. There is 106 acre-feet of alluvium with a mean specific yield of 28 percent, and a maximum water absorbing capacity of 29 acre-feet or 7 acre-feet per mile of reach. Channel slope is insensitive to changes in geological material beneath it or to changes in flow regime. Channel cross section is highly sensitive to geology and flow regime. Transmission losses were highly correlated to volume of inflow.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / Almost all runoff from semiarid rangeland watersheds in southern Arizona results from intense highly variable thunderstorm rainfall. Abstractions, or transmission losses, are important in diminishing streamflow, supporting riparian vegetation and providing natural groundwater recharge. A flood routing procedure is developed using data from the walnut gulch experimental watershed, where flood movement and transmission losses are represented by a system using storage in the channel reach as a state variable which determines loss rates. Abstractions are computed as a cascade of general components in linear form. Wide variation in the parameters of this linear model with increasing inflow indicates that a linear relation between losses and storage is probably incorrect for ephemeral channels.