DIFFERENCES IN WARM-SEASON,RAINSTORM-GENERATED STORMFLOWS FOR NORTHEASTERN ILLINOIS URBANIZED BASINS1

ABSTRACT: Precipitation, streamflow, and population data were analyzed over the 1941–1990 period to determine whether changes in stormflows and net (post. minus pre-rainstorm) stormflows, associated with warm-season large rainstorms, were similar for two urbanized northeastern Illinois basins. Warm season large rainstorms were defined as April through October rainfall events in which ? 5.1 cm occurred in a 48-hour period over the basin. To minimize differences associated with varying large rainstorm amounts over time, the net sthrmflow for each event was divided by the large rainstorm amount. This ratio, Ui, indicated that the two urbanized basins experienced significant, yet different, increases (102 percent and 49 percent) in flow amount per centimeter of rainfall from 1941–1965 to 1966–1990. Results of a regression analysis between Ui and population showed that the increase in U_i per 100,000 increase in population ranged from 0.59 to 0.67 m³s^-1 per cm of rainfall for the two basins. These results demonstrate the varying degree of change that urban planners can expect in stormflows associated with large warm season rainstorms for areas undergoing urbanization.     

Potential environmental benefits of ionophores in ruminant diets

A concern of the USEPA is the volatilization of NH3 from animal manure and CH4 produced from ruminal fermentation. Excess N in the environment has been associated with adverse effects on human health, and CH4 and N2O emissions are sources of greenhouse gases. The objectives of this paper are to summarize and quantify the benefits of ionophores, principally monensin, in decreasing NH3 and CH4 emissions to the environment and reducing resource utilization in cattle (Bos spp.) production. The data indicate that monensin in the diets of ruminants may decrease protein degradation in the rumen and may increase feed protein utilization by an average of 3.5 percentage units. These changes would have an effect in reducing N losses and decreasing fecal N and the amount of protein that must be fed to meet animal requirements. Additionally, CH4 is produced by enteric fermentation in ruminants, which is responsible for about 33 to 39% of CH4 emissions from agriculture. Ionophores can reduce CH4 production by 25% and decrease feed intake by 4% without affecting animal performance. The inclusion of monensin in beef and dairy cattle diets may benefit air quality by reducing CH4 and N emissions and water quality by reducing N in manure, which can potentially leave the farm through leaching into ground water and through runoff into surface water.     

TRENDS IN FRESHWATER INFLOW TO SAN FRANCISCO BAY FROM TUE SACRAMENTO-SAN JOAQUIN DELTA1

ABSTRACT: Outflow from the Sacramento-San Joaquin river system (Delta outflow) provides about 90 percent of the freshwater flow to San Francisco Bay. Because this river system also supplies most of the water used in California, some believed that annual freshwater flow to the Bay had declined by as much as 50 to 60 percent as water use increased. Consequently, we studied trends in actual Delta outflow and precipitation for the period 1921 to 1986, which is when Delta outflow data are available. We found that there has been no decrease in the annual Delta outflow over this period. In fact, a statistically significant increase in annual Delta outflow of 87 cfa/yr has occurred during the period 1921 to 1986. One reason that Delta outflow has increased is because precipitation has increased faster than water use. Other contributing factors include increased runoff from land use changes, water imports from other areas, and the redistribution of ground water. In addition, statistically significant seasonal trends in Delta outflow were found. Over the period 1921–1986 Delta outflow decreased in April and May and increased from July through November. Changes in other months were not statistically significant. These seasonal changes result primarily from the operation of upstream flood control and water development projects, which store water in the spring and release it in the summer and fall. These seasonal changes are also influenced by a climatic shift that has decreased spring snowmelt runoff and increased late summer through winter precipitation.     

Farmer decision making and spatial variables in northern Thailand

This research has two interrelated objectives. The first is to determine the extent to which a relationship exists between farmer characteristics and farming practices in three villages in northern Thailand. The second is to use standard statistical methods for incorporating spatial variables into the analysis and to assess the effects of these variables on farmer decision making. The data base includes information on the location and size of villages, roads, streams, and fields; a digital elevation model with information on elevation, slope, and aspect; and information keyed to individual fields on crops and cropping methods and the ethnicity, income, and religion of farmers. The map data (517 plots) were entered into a computerized geographic information systems (GIS). Results suggest several hypotheses about the relationships between land use and owner characteristics. More significantly, the study concludes that spatial analysis appears to be most useful when the dependent variable is either continuous or ordinal. The outlook is not quite as optimistic when the dependent variable is a nonordinal categorical variable. Before spatial analysis can be applied regularly to social science data, better computational tools need to be developed.     

Forest-dweller demographics in West Kalimantan,Indonesia

This study sought to ascertain, from census and other data, the number of people living on state-claimed forest land (SCFL) in West Kalimantan in the outer islands of Indonesia. One aim was to determine why data collection is problematic. In 1990 the outer islands accounted for 38% of total population, 93% of its land mass, and 98% of its forests. 72% of the land mass of the outer islands was designated SCFL. Kalimantan has 38.5 million hectares of SCFL, while West Kalimantan has 9.2 million hectares, or 63% of the land area of the province. In 1990, 3.2 million people lived in West Kalimantan. Two sets of forest cover maps and census statistics at the village level were integrated into the geographic information system (GIS) technology by district and regency boundaries and the location of villages. The fieldwork was conducted in Sengah Temila District in Pontianak Regency and Simpang Hulu District in Ketapang Regency. Four methods were used to estimate forest populations: 1) estimating gross population density, 2) mapping forest villages, 3) adjusting density to account for uneven population distribution, and 4) estimating population densities for specific villages and generalizing to the province level. Methods 3 and 4 gave the most reasonable estimates. Population varied from 650,000 to 1 million. Government census statistics proved to be accurate representations of human population. The 1:50,000 scale of topological maps of West Kalimantan correctly identified the location of villages listed in the census. The Indonesian Ministry of Forestry's forest-planning maps and the RePPProT maps both reported similar SCFL. The GIS technology was useful in integrating data from several sources. The lack of knowledge was not due to political or institutional interests.