EVALUATING HSPF IN AN ARID,URBANIZED WATERSHED1

ABSTRACT: The Hydrologic Simulation Program‐FORTRAN (HSPF) is a powerful time variable hydrologic model that has rarely been applied in arid environments. Here, the performance of HSPF in southern California was assessed, testing its ability to predict annual volume, daily average flow, and hourly flow. The model was parameterized with eight land use categories and physical watershed characteristics. It was calibrated using rainfall and measured flow over a five‐year period in a predominantly undeveloped watershed and it was validated using a subsequent 4‐year period. The process was repeated in a separate, predominantly urbanized watershed over the same time span. Annual volume predictions correlated well with measured flow in both the undeveloped and developed watersheds. Daily flow predictions correlated well with measured flow following rain events, but predictions were poor during extended dry weather periods in the developed watershed. This modeling difficulty during dry‐weather periods reflects the large influence of, and the poor accounting in the model for, artificially introduced water from human activities, such as landscape overwatering, that can be important sources of water in urbanized arid environments. Hourly flow predictions mistimed peak flows, reflecting spatial and temporal heterogeneity of rainfall within the watershed. Model correlation increased considerably when predictions were averaged over longer time periods, reaching an asymptote after an 11‐hour averaging window.     

Applicability of a Septic Tank/Engineered Wetland Coupled System in the Treatment and Recycling of Wastewater from a Small Community

A septic tank (ST)/engineered wetland coupled system used to treat and recycle wastewater from a small community in Dar es Salaam, Tanzania was monitored to assess its performance. The engineered wetland system (EWS) had two parallel units each with two serial beds packed with different sizes of media and vegetated differently. The larger-sized medium bed was upstream and was planted with Phragmites (reeds) and the smaller-sized medium bed was downstream and was planted with Typha (cattails). The ST/EWS coupled system was able to remove ammonia by an average of 60%, nitrate by 71%, sulfate by 55%, chemical oxygen demand by 91%, and fecal coliform as well as total coliform by almost 100%. The effluent from the ST/EWS coupled system is used for irrigation. Notably, users of the recycled irrigation water do not harbor any negative feelings about it. This study demonstrates that it is possible to treat and recycle domestic wastewater using ST/EWS coupled systems. The study also brings attention to the fact that an ST/EWS coupled system has operation and maintenance (O&M) needs that must be fulfilled for its effectiveness and acceptability. These include removal of unwanted weeds, harvesting of wetland plants when the EWS becomes unappealingly bushy, and routine repair.     

Variations in jail sentences and the probability of re-arrest for driving while intoxicated

OBJECTIVE: The probability of re-arrest for driving while intoxicated (DWI) is compared for four different groups of individuals classified by whether the individual was convicted and, if so, the type of sentence received. METHOD: Subsequent re-arrests for DWI were examined for all individuals whose index arrest for DWI had occurred between 1994 and 2001 in a county in New Mexico. The groups included (1) those convicted as a result of the index arrest and sentenced to a 28-day jail/treatment program (N (#)=(#) 2,703); (2) all those not convicted as a result of the index arrest (N = 709); (3) those who were convicted but not sentenced to jail (N = 1,047); and (4) those convicted and sentenced to jail (N = 1,290). RESULTS: Adjusting for covariates of BAC, number of prior arrests, ethnicity, age, and sex, the probability of not being re-arrested was greatest among those sentenced to the jail/treatment program (Group 1), next highest in the two groups convicted but not sentenced to jail/treatment (Groups 3 and 4), and lowest in the group that was not convicted (Group 2). Length of jail sentence among people convicted but not sentenced to the jail/treatment program was unrelated to the probability of re-arrest. CONCLUSION: Conviction for DWI, regardless of the sentence, appears to reduce the probability of re-arrest, and being sentenced to a multi-modal treatment/incarceration program further reduces the probability of re-arrest. However, the other types of sentences do not appear to differ in their impact on probability of re-arrest.     

Evolutionary divergence among lineages of the ocean sunfish family,Molidae (Tetraodontiformes)

Ocean sunfish, family Molidae, are enigmatic members of the epipelagic fauna of all tropical and temperate oceans. A study, begun in 1998, initially focused on the population genetics of Mola mola Linnaeus 1758 immediately indicated high levels of genetic divergence in the d-loop and cytochrome b mitochondrial genes. This preliminary effort was expanded to include Masturus lanceolatus Liénard 1840, Ranzania laevis Pennant 1776, and representative sequences of other Tetraodontiformes. Analysis of the sequence data confirms that there are two species in the genus Mola, Mola mola and M. ramsayi Giglioli 1883, with the latter presumed to be limited to the southern hemisphere. There is an indication of inter-ocean subdivision within both species originating 0.05–0.32 and 1.55–4.10 million years ago, respectively. Given limited sample sizes, however, the divergence estimates are minimums and the isolating mechanisms remain speculative. The systematic analysis provided strong support for the sister taxa relationship between genera Masturus and Mola and the basal position of the genus Ranzania within the family, as well as the sister group relationship of the Tetraodontiform families Tetraodontidae + Diodontidae to the Molidae.     

Dynamics of P, Al, and Fe during High Discharge Episodic Acidification at the Bear Brook Watershed in Maine, U.S.A.

Phosphorus (P), aluminum (Al), and iron (Fe) stream chemistry were assessed for high discharge snowmelt events at the Bear Brook Watershed, Maine (BBWM) during December 2001 and February 2002 and compared with results from a January 1995 study of the same streams. The West Bear catchment has been subjected to artificial acidification since 1989. The East Bear catchment is the untreated reference. Total (acid soluble) Al, Fe, and P were positively correlated with discharge during the 2001–2002 events. However, dissolved P concentrations remained low (≤0.1 μmol L^-1) during high discharge events as pH decreased in both streams.For example, in 2001, total P concentration increased to 1.7 μmol L^-1 during the rising limb of the hydrograph in West Bear, approximately five times the value in East Bear. During the same event, in West Bear and East Bear dissolved Al concentrations increased to 21 and 6.3 μmol L^-1, respectively, while total Al concentrations increased to 166 and 30 μmol L^-1, respectively. Dissolved Fe concentrations remained ≤0.9 μmol L^-1 in both streams during all study events. However, total Fe concentrations in 2001 increased to 239 and 4.1 μmol L^-1 for West Bear and East Bear, respectively. Total Al and Fe declined parallel to total P after peaking during all study periods. Nearly all of the base cations were in dissolved form during the three events, indicating that total Al in West and East Bear Brooks is not associated with primary minerals such as feldspars. We conclude that particulate Al, Fe, and P are chemically linked during transport at high discharge in these episodically and chronically acidified streams.     

Teaching Approaches in Geography and Students’ Environmental Attitudes

In a study which examines the pattern of geography teaching at the Advanced Level in Hong Kong and assesses the relative effectiveness of didactic and enquiry teaching approaches that are used by the teachers concerned for the development of positive values towards the environment, the question was asked as to whether or not enquiry is more effective than didactic approaches for the development of environmental values, in both the short and long terms, for students as a whole and for students from different ability ranges. Questionnaire surveys and interviews were conducted to obtain data from students after they were taught a topic on people and the environment in the curriculum, with the approach chosen by their teachers. Results show that the enquiry approach was effective with the lower to medium ability classes in the short term but students who were taught didactically performed better in more areas in the longer term. The possible causes for this pattern are discussed and suggestions for improving the effectiveness of enquiry approaches in a high-pressure, examination-oriented classroom environment are offered.     

TREE‐RING BASED RECONSTRUCTIONS OF INTERANNUAL TO DECADAL SCALE PRECIPITATION VARIABILITY FOR NORTHEASTERN UTAH SINCE 1226 A.D.1

ABSTRACT: Samples from 107 piñon pines (Pinns edulis) at four sites were used to develop a proxy record of annual (June to June) precipitation spanning the 1226 to 2001 AD interval for the Uinta Basin Watershed of northeastern Utah. The reconstruction reveals significant precipitation variability at interannual to decadal scales. Single‐year dry events before the instrumental period tended to be more severe than those after 1900. In general, decadal scale dry events were longer and more severe prior to 1900. In particular, dry events in the late 13th, 16th, and 18th Centuries surpass the magnitude and duration of droughts seen in the Uinta Basin after 1900. The last four decades of the 20th Century also represent one of the wettest periods in the reconstruction. The proxy record indicates that the instrumental record (approximately 1900 to the Present) underestimates the potential frequency and severity of severe, sustained droughts in this area, while over representing the prominence of wet episodes. In the longer record, the empirical probability of any decadal scale drought exceeding the duration of the 1954 through 1964 drought is 94 percent, while the probability for any wet event exceeding the duration of the 1965 through 1999 wet spell is only 1 percent. Hence, estimates of future water availability in the Uinta Basin and forecasts for exports to the Colorado River, based on the 1961 to 1990 and 1971 to 2000 “normal” periods, may be overly optimistic.     

Unit costs for decontamination and dismantlement of structures

A series of relationships have been developed for estimating unit costs for decontamination and dismantlement (D&D) of a number of structure types. These relationships may be applied in the absence of other data to obtain rough order-of-magnitude cost estimates for D&D activities. The relationships were developed using D&D costs estimated for various types of buildings at the U.S. Department of Energy Fernald site. These unit costs take into account the level of radiological contamination as well as the building size and type.     

Macroinvertebrate biomonitoring in intermittent coastal plain streams impacted by animal agriculture

Little attention has been given to the ecology of intermittent coastal plain streams in the southeastern United States, and it is not known whether available macroinvertebrate biomonitoring methods reliably detect degradation in these streams. This study compared differences in biomonitoring metrics between reference and agricultural streams, and between the flow period (January-April) and the intermittent flow period (May-December). Percentages of crustaceans, isopods, and Ephemeroptera-Plecoptera-Trichoptera (EPT) were significantly higher at the reference site than the two most impacted sites during the flow period, probably resulting from the abundance of leaf litter and lower temperatures. During this same period, the agriculturally impacted sites had a significantly higher percentage of dipterans--a group that thrives in the silty, nutrient-rich waters. Four metrics (percent Crustacea, Isopoda, Diptera, and EPT) had no overlap between values for the most impacted and the least impacted sites during the flow period, but no metrics were able to detect more discrete differences among sites. Sites were physically and biologically similar during the intermittent period when natural stresses (i.e., stagnant water, high temperatures, low dissolved oxygen) were high, with many metrics, such as percentages of dominant family, burrowers, chironomids, and dipterans becoming similar at all sites. Our findings indicate that development of a better understanding of invertebrate fauna in reference conditions and of the natural variation in intermittent streams is necessary to develop effective biomonitoring programs for these systems.