Scientist and policy-maker response types and times in suburban watersheds

Differences between scientist and policy-maker response types and times, or the “how” and “when” of action, constrain effective water resource management in suburbanizing watersheds. Policy-makers are often rushed to find a single policy that can be applied across an entire, homogeneous, geopolitical region, whereas scientists undertake multiyear research projects to appreciate the complex interactions occurring within heterogeneous catchments. As a result, watershed management is often practiced with science and policy out of synch. Meanwhile, development pressures in suburban watersheds create changes in the social and physical fabric and pose a moving target for science and policy. Recent and anticipated advances in the scientific understanding of urbanized catchment hydrology and pollutant transport suggest that management should become increasingly sensitive to spatial heterogeneities in watershed features, such as soil types, terrain slopes, and seasonal watertable profiles. Toward this end, policy-makers should encourage funding scientific research that characterizes the impacts of these watershed heterogeneities within a geopolitical zoning and development framework.     

Computer simulation of the cumulative effects of brushland fire-management policies

A mathematical model simulates the cumulative volume of debris produced from brushland watersheds. Application of this model to a 176-km² (0.678 = mi²) watershed along the southern flank of the Central San Gabriel Mountains permits assessment of expected debris production associated with alternative fire-management policies. The political implications of simulated debris production are evaluated through a conceptual model that links interest groups to particular successional stages in brushland watersheds by means of the resources claimed by each group. It is concluded that in theory, a rotation burn policy would provide benefits to more interest groups concerned about southern California's brushland watersheds than does the current fire exclusion policy.This research was supported by the College of Agriculture and Life Sciences, University of Wisconsin-Madison, and by the Office of Water Research and Technology, USDI, under the Allotment program of Public Law 88–379, as amended, and by the University of California. Water Resources Center, as a part of Office of Water Research and Technology Project No. A-058-CAL and Water Resources Center Project UCAL-WRC-499. Support was also provided by the California Agricultural Experiment Station, Berkeley, California.     

FLOODING PROBLEMS IN A SMALL URBAN WATERSHED-DOAN BROOK,CLEVELAND, OHIO1

ABSTRACT: Analysis of a small urban watershed's flooding was undertaken to determine causes and solutions to this serious environmental hazard affecting University Circle, the cultural heart of Greater Cleveland. Doan Brook is a small, highly disturbed urban stream draining 11.3 square miles. Much of the stream coridor and associated park land is owned by the public. The upper watershed lies in the communities of Shaker Heights and Cleveland Heights who lease park land from Cleveland. Two 50-year floods seriously affected the Circle area in August 1975 generating over $1 million in damages. These events resulted from excessive rainfall triggering rapid earth movement of valley walls in the upper watershed, decreased basin lag time from the infilling of several small upland lakes, a seriously undersized stream channel and storm culvert (at University Circle), and complex institutional arrangements between the three communities in the watershed. Suggestions are presented for a methodology to resolve the technical aspects of the flooding problem.     

GEOMORPHIC PARAMETERS PREDICT HYDROGRAPH CHARACTERISTICS IN THE SOUTHWEST1

ABSTRACT: Critical design characteristics of ephermal runoff such as hydrograph rise time, duration, mean peak discharge, volume, peak-volume ratio, and maximum flood were related to physical basin parameters such as area, shape, slope, drainage density, basin relief, stream length, and combinations of these in intermontane watersheds representative of the Mexican Highland section of the Basin and Range Province. Parameters used were restricted to those easily obtainable from maps or aerial photographs. A parameter expressing basin shape and size was developed which proved to be as accurate a predictor as others used in existing prediction equations tested and was simpler and faster to derive. Simple prediction equations derived for hydrograph characteristics were all significant except for volume at the 5% level; three were significant at the 1% level. Relationships determined are applicable in semi-arid basins of the Southwest up to 60 square miles (155 km²) in area.     

ISOLATING THE RANDOM RAMSTORM COMPONENT FROM BASIN RESPONSE FACTORS IN RAINFALLRUNOFF DATA1

ABSTRACT: Gaged watersheds can provide information as to geomorphic, and geologic influence on the spatial variability of rainfall-runoff relationships. However, correlations between raingages distributed throughout the basin, and stream discharge are influenced by both storm patterns and drainage basin characteristics. Factor analysis has been applied to rainfall-runoff relationship to isolate the storm pattern from a basin response factor. Comparing two periods of time separated by eight years reveals relative stability in the rainfall attenuation (basin response) factor, while storm patterns for the two periods of record are quite disparate.     

SEISMIC REFRACTION ANALYSIS OF WATERSHED MANTLE RELATED TO SOIL,GEOLOGY AND HYDROLOGY1

ABSTRACT: An extensive hammer seismic refraction survey was carried out in three contiguous watersheds (217, 89, and 190 acres) on a laccolith near Sturgis, South Dakota to test its utility in rugged mountain terrain. Isopachs (lines connecting points of equal mantle thickness), area-elevation curves (hypsometry), and structure contours were used together with drill cores, petrography, hydrographs, and soil information to interpret the nature and role of porous mantle in the waterflow behavior of the watersheds. Refraction profiles produced only one geologically meaningful seismic contrast within the loccolith. Drill cores indicated a shallow stony profile on a sheeted horizon terminating on isotropic crystalline rock impervious except for tight joints. Means of refraction and core interpretations were not statistically different. Apparent seismic discontinuities deeper within the bedrock lacked geological identity. Storm hydrographs and water yields are better related to soil type differences and porous mantle distribution than to average porous mantle depth. On the other hand, slope of flow-duration curves correlate with average porous mantle depth. Porous mantle isopachs also indicate that measured flow from each basin is total area flow. Thus, porous mantle isopachs and hypsometry, and soil type delineation are complimentary in our interpretation of watershed behavior.     

SOIL MOISTURE ACCOUNTING COMPONENT OF THE USDAHL-74 MODEL OF WATERSHED HYDROLOGY1

ABSTRACT: Soil moisture in two layers of a soil near Chickasha, Oklahoma, was simulated, using USDAHL-74 Model of Watershed Hydrology. Weekly values computed for both layers compared well with those observed during the 15-month period. Certain key parameters required adjustments in the model which illustrate the need for accurate input information. The experiment demonstrates that the model, which has previously given good results in continuous streamflow prediction on watersheds up to 100 square miles, can also compute soil moisture continuously at a site. This capability suggests other model uses, for example, in monitoring the disposition of applied chemicals.     

RESEARCH ISSUES IN FOREST HYDROLOGY1

ABSTRACT: This paper explores a range of forest hydrology issues and identifies my concepts of the field's most pressing research needs. I extend the topic to include teaching and education in the broader sense because current teaching is usually part of the researcher's portfolio and because education involves that of both the research scientist and a broader audience. I consider the primary research, education, and service roles of the forest hydrologist also within a range of domains or, as I prefer to identify them, scales: (1) the molecular or pore level; (2) hydrological process; (3) watershed function; (4) global considerations, and (5) the human dimension which, while not actually a scale itself, embraces, is important to, and is affected by the first four. All are topics screaming for attention by researchers, educators, and practitioners. I shall here focus on the middle three.     

USE OF STAGE DATA TO CHARACTERIZE HYDROLOGIC CONDITIONS IN AN URBANIZING ENVIRONMENT1

ABSTRACT: This paper presents the results of a study on the use of continuous stage data to describe the relation between urban development and three aspects of hydrologic condition that are thought to influence stream ecosystems—overall stage variability, stream flashiness, and the duration of extreme‐stage conditions. This relation is examined using data from more than 70 watersheds in three contrasting environmental settings—the humid Northeast (the metropolitan Boston, Massachusetts, area); the very humid Southeast (the metropolitan Birmingham, Alabama, area); and the semiarid West (the metropolitan Salt Lake City, Utah, area). Results from the Birmingham and Boston studies provide evidence linking increased urbanization with stream flashiness. Fragmentation of developed land cover patches appears to ameliorate the effects of urbanization on overall variability and flashiness. There was less success in relating urbanization and streamflow conditions in the Salt Lake City study. A related investigation of six North Carolina sites with long term discharge and stage data indicated that hydrologic condition metrics developed using continuous stage data are comparable to flow based metrics, particularly for stream flashiness measures.     

ASSESSING FLOOD MITIGATION ALTERNATIVES IN SHIJR AREA IN METROPOLITAN TAIPEI1

The Keelung River Basin in northern Taiwan lies immediately upstream of the Taipei metropolitan area. The Shijr area is in the lower basin and is subject to frequent flooding. This work applies micromanagement and source control, including widely distributed infiltration and detention/ retention runoff retarding measures, in the Wudu watershed above Shijr. A method is also developed that combines a genetic algorithm and a rainfall runoff model to optimize the spatial distribution of runoff retarding facilities. Downstream of Wudu in the Shijr area, five dredging schemes are considered. If 10‐year flood flows cannot be confined in the channel, then a levee embankment that corresponds to the respective runoff retarding scheme will be required. The minimum total cost is considered in the rule to select from the regional flood mitigation alternatives. The results of this study reveal that runoff retarding facilities installed in the upper and middle parts of the watershed are most effective in reducing the flood peak. Moreover, as the cost of acquiring land for the levee embankment increases, installing runoff retarding measures in the upper portion of the watershed becomes more economical.