BIOLOGICAL AND ECONOMIC IMPLICATIONS OF SACRAMENTO WATERSHED MANAGEMENT OPTIONS1

ABSTRACT: This paper brings together spatially and temporally explicit mechanistic models of hydrodynamic, water quality, and ecological processes with an economic model to examine water management alternatives for California's Sacramento River and Delta ecosystem, a large‐scale watershed. Overallocated water supplies in most years, combined with increasing demand for water for environmental purposes, have created a politically charged atmosphere and a need for quantitative assessment of the implications of policy alternatives. By developing and analyzing a common set of policy scenarios, this integrated framework allows us to consider tradeoffs between agricultural economic factors, water quality, and population dynamics for two at‐risk fish species. We analyze two rather extreme types of policy options; one involves structural modifications to change the flow of water within the watershed but no change in water diversions, while the other reallocates water from agricultural users to fish and wildlife. Results suggest that substantial environmental improvements could be made at a relatively modest cost to farmers (1 to 4 percent reductions in revenues) but that those costs could be significant locally. In addition to tradeoffs between farmers and environmental interests, results suggest that policy makers may need to balance competing environmental objectives.     

WATER AND WATER RIGHTS TRANSFERS: A NEW POLICY FOR NEBRASKA1

ABSTRACT: Nebraska has abundant supplies of high quality surface and ground water. The U.S. Supreme Court decision in 1982, declaring ground water to be an article of commerce, is widely perceived as giving neighboring states easier access to Nebraska water. Some neighboring states, particularly Colorado and Wyoming, are in water short situations. Additionally, current legal restrictions on certain types of transfers within the State could be inhibiting the “highest and best use” of Nebraska's water. Thus, in 1987 the Nebraska Legislature called for the development of a new water policy for Nebraska that would promote the economically efficient use of water, yet protect the environment as well as the rights of individuals (for example, third parties) and the public. Through an interagency study employing an extensive public involvement process, a policy to be recommended to the Legislature in 1989 emerged. The policy revises the basic definition of water rights and transfers and eliminates most of the inconsistencies in the water allocation system by treating most types of water resources, most types of water users, and most locations of use similarly in the permitting process. (The principal exception is the individual irrigator using ground water on the overlying land where overlying land is one government surveyed section; such use is not defined to be a transfer nor is a permit required.) An impact assessment would be required of most new water uses except on site uses of ground water. Compensation measures could be specified as a condition of the permit where appropriate. The permit would be issued only if the benefits of the proposed transfer clearly outweigh adverse effects that could not be avoided or effectively compensated. The policy allows for the sale or lease of “salvaged” water. It calls for the State to facilitate transfers by acting as a clearinghouse for potential buyers and sellers, and it allows the State to sponsor water projects. An annual fee to be paid by many water users, in order to provide a fund for compensation and for state sponsored water projects, was proposed. However, it met with extensive opposition. Thus, the policy recommends only that the Legislature examine potential funding programs and equitable user fees.     

SOME HYDROLOGIC IMPACTS OF PLOWING RANGELAND SOILS1

ABSTRACT: Rainfall simulator studies were conducted during 1982 and 1983 on agricultural and native rangeland soils of the same soil series in northern Utah. Results indicate that the same soil series mapped at different locations on agricultural land will have similar 10, 20, and 30 minute infiltration rates and similar interrill erosion rates. Seasonal differences in infiltration and erosion rates were significant. Comparisons between agricultural and native soils were complicated by three-way statistical interactions. Seasonal variations in both infiltration rates and erosion rates were greatest on agricultural soils. Of four soil series on native rangeland, only one showed significant seasonal variation in infiltration rates, while erosion rates were similar across all seasons for all soil series. Soil and cover factors important in predicting infiltration and erosion were identified.     

SIMULATION OF REGIONAL GROUND WATER FLOW IN BEDROCK,SOUTHWESTERN NEW YORK-NORTHWESTERN PENNSYLVANIA1

ABSTRACT: This paper presents the results of steady-state three-dimensional computer simulations to determine the hydrogeologic setting of formation water in the hydrocarbon producing formations of southwestern New York and northwestern Pennsylvania. Recharge areas for the regional ground water flow systems in the study area are the Valley Heads Moraine and Allegheny uplands; discharge areas are Lakes Erie and Ontario to the north and the northern margin of the Appalachian basin to the south. Simulated ground water flow in all model layers moves north from the ground water divide on the Valley Heads Moraine towards Lake Erie at a rate from 10^?-⁶ to 10^?-³ ft/day. South of the divide intermediate-scale and local-scale flow systems occur in the upper 4000 feet of the stratigraphic section and the directions of ground water flow diverge towards major rivers and other topographically low areas.     

FECAL COLIFORM RELEASE FROM CATTLE FECAL DEPOSITS1

ABSTRACT: Cowpies molded to a standard configuration and size were subjected to simulated rainfall, and the fecal coliform counts were determined using the most probable number (MPN) method of enumeration. The standard cowpie deposits were exposed to simulated rainfall once at ages 2 through 100 days. The effects of rainfall intensity and recurrent rainfall were also tested. Naturally-occurring fecal deposits were also tested to compare their results with those from the standard cowpies. A log-log regression was found to describe the decline in peak fecal coliform release with fecal deposit age. The 100-day-old fecal deposits produced peak counts of 4,200 fecal coliform per 100 milliliters of water. This quantity of release is minimal compared to the release from fresher fecal material. Rainfall intensity had little effect on peak fecal coliform release from fecal deposits that were 2 or 10 days old. At age 20 days the effect of rainfall intensity was significant; the highest intensity gave the lowest peak counts, and the lowest intensity gave the highest peak counts. The effect of rainfall intensity appears to be related to the dryness of the fecal deposits. Peak fecal coliform counts were significantly lowered when the fecal deposits were rained on more than once. This decline was thought to be produced by the loss of bacteria from the fecal deposits during the previous wettings. Standard cowpies produced a peak release regression that was not significantly different from the regression for the natural fecal deposits. Apparently, grossly manipulating the fecal deposits did not significantly change the release patterns.     

Survival Model for Foot and Leg High Rate Axial Impact Injury Data

Objectives: Understanding how lower extremity injuries from automotive intrusion and underbody blast (UBB) differ is of key importance when determining whether automotive injury criteria can be applied to blast rate scenarios. This article provides a review of existing injury risk analyses and outlines an approach to improve injury prediction for an expanded range of loading rates. This analysis will address issues with existing injury risk functions including inaccuracies due to inertial and potential viscous resistance at higher loading rates.

Methods: This survival analysis attempts to minimize these errors by considering injury location statistics and a predictor variable selection process dependent upon failure mechanisms of bone. Distribution of foot/ankle/leg injuries induced by axial impact loading at rates characteristic of UBB as well as automotive intrusion was studied and calcaneus injuries were found to be the most common injury; thus, footplate force was chosen as the main predictor variable because of its proximity to injury location to prevent inaccuracies associated with inertial differences due to loading rate. A survival analysis was then performed with age, sex, dorsiflexion angle, and mass as covariates. This statistical analysis uses data from previous axial postmortem human surrogate (PMHS) component leg tests to provide perspectives on how proximal boundary conditions and loading rate affect injury probability in the foot/ankle/leg (n = 82).

Results: Tibia force-at-fracture proved to be up to 20% inaccurate in previous analyses because of viscous resistance and inertial effects within the data set used, suggesting that previous injury criteria are accurate only for specific rates of loading and boundary conditions. The statistical model presented in this article predicts 50% probability of injury for a plantar force of 10.2 kN for a 50th percentile male with a neutral ankle position. Force rate was found to be an insignificant covariate because of the limited range of loading rate differences within the data set; however, compensation for inertial effects caused by measuring the force-at-fracture in a location closer to expected injury location improved the model's predictive capabilities for the entire data set.

Conclusions: This study provides better injury prediction capabilities for both automotive and blast rates because of reduced sensitivity to inertial effects and tibia–fibula load sharing. Further, a framework is provided for future injury criteria generation for high rate loading scenarios. This analysis also suggests key improvements to be made to existing anthropomorphic test device (ATD) lower extremities to provide accurate injury prediction for high rate applications such as UBB.     

Implications of Functional Capacity Loss and Fatality for Vehicle Safety Prioritization

Objective: We investigate the use of the Functional Capacity Index (FCI) as a tool for establishing vehicle safety priorities by comparing the life year burden of injuries to the burden of fatality in frontal and side automotive crashes. We demonstrate FCI’s utility by investigating in detail the resulting disabling injuries and their life year costs.

Methods: We selected occupants in the 2000–2013 NASS-CDS database involved in frontal and side crashes, merged their injuries with FCI, and then used the merged data to estimate each occupant’s overall functional loss. Lifetime functional loss was assessed by combining this measure of impairment with the occupants’ expected future life spans, estimated from the Social Security Administration’s Actuarial Life Table.

Results: Frontal crashes produce a large number of disabling injuries, particularly to the lower extremities. In our population, these crashes are estimated to account for approximately 400,000 life years lost to disability in comparison with 500,000 life years lost to fatality. Victims of side crashes experienced a higher rate of fatality but a significantly lower rate of disabling injury (0.3 vs. 1.0%), resulting in approximately 370,000 life years lost to fatality versus 50,000 life years lost to disability.

Conclusions: The burden of disabling injuries to car crash survivors should be considered when setting vehicle safety design priorities. In frontal crashes this burden in life years is similar to the burden attributable to fatality.     

Reproductive biology of the tiger shark (Galeocerdo cuvier) in Hawaii

The tiger shark (Galeocerdo cuvier) is the largest shark in the family Carcharhinidae and the only carcharhinid with aplacental viviparous (ovoviviparous) reproduction. Despite its size and prevalence, many details of tiger shark reproductive biology are unknown. Size at maturity and litter size have been reported by several authors, but a lack of large numbers of pregnant females has made it difficult to determine gestation period, seasonality, and timing of the female reproductive cycle. Here we analyze data from shark control program fishing and incidental catches in Hawaii (n = 318) to construct the most complete picture of tiger shark reproduction to date. Males reached maturity at approximately 292 cm total length (TL) based on clasper calcification, whereas females matured between 330 and 345 cm TL based on oviducal gland and uterus widths. Litter sizes ranged from 3 to 57 with a mean of 32.6 embryos per litter. Data from 23 litters from various months of the year indicate that tiger sharks are usually 80–90 cm TL at birth, and that the gestation period is 15–16 months. Mating scars were observed in January–February and sperm is presumably stored for 4–5 months until ovulation takes place in May–July. Gestation begins in June–July and pups are born in September–October of the following year. Our data suggest that female tiger sharks in Hawaii give birth only once every three years. This could have major implications for conservation and management of this species, as it suggests that tiger shark fecundity is 33% lower than previously thought. This could greatly reduce the ability of this species to rebound from fishing pressure.

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