Recent wrc_contributions items

River Seepage Investigation

Thu, 12 May 2011 00:00:00 +0000

Seepage from rivers and natural channels is a serious problem in the Sacramento Valley of California. Impairment of land use occurs along the Sacramento, Feather, Yuba and Bear Rivers as a result of intermittent periods of high ground water or ponded surface water. When channel levels exceed the adjacent ground surface elevation, water moves through and under the confining levels into adjacent lands. If drainage facilities are inadequate, the soil becomes saturated and water often ponds on the surface. The water damages orchards and perennial and annual crops, and prevents working of land, resulting in delays in or prevention of normal planting of annual crops.

From High Rise to Coast: Revitalizing Riveira da Barcarena

Wed, 25 Aug 2010 00:00:00 +0000

The Lisbon metropolitan region has grown rapidly in population since 1970, due largely to the immigration of people from former Portuguese colonies in Africa and from rural areas of the country in pursuit of higher living standards. Much of this population growth was accommodated clustered high-rise apartment blocks (many unpermitted) in the region west of Lisbon, in the municipalities Oeiras, Cascais, Sintra, and Amadora. These developments were largely unplanned, often did not provide for sewage treatment, and lack adequate mass transit or urban amenities such as parks and other open spaces. Moreover, because the main transport axes run east-west, it is difficult for residents of these apartment blocks to go the relatively short distance southward to the coast (e.g., only 10 km from Cacém to the coast).

This region is drained by a set of subparallel streams (each draining about 20-50 km2), flowing roughly north-south through deeply incised valleys to debouch into the...

Numerical Simulation of Land Subsidence in the Los Banos-Kettleman City Area, California

Tue, 24 Mar 2009 00:00:00 +0000

Land subsidence caused by the excessive use of groundwater resources has traditionally caused serious and costly damage to the Los Banos-Kettleman City area of California's San Joaquin Valley. Although the arrival of surface water from the Central Valley Project has reduced subsidence in recent decades, the growing instability of surface water supplies has refocused attention on the future of land subsidence in the region. This report develops a three-dimenslonal, numerical simulation model for both groundwater flow and land subsidence. The simulation model is calibrated using observed data from 1972 to 1998. A probable future drought scenario is used to consider the effect on land subsidence of three management alternatives over the next thirty years. Maintaining present practices virtually eliminates unrecoverable land subsidence, but with a growing urban population to the south and concern over the ecological implications of water exportation from the north, it does not...

A Living Mediterranean River: Restoration and Management of the Rio Real in Portugal to Achieve Good Ecological Condition

Mon, 16 Mar 2009 00:00:00 +0000

In Mediterranean climates, mild year-round temperatures support comfortable human settlement with rich agricultural regions. The climate’s long summer drought, seasonal river flow, high inter-annual variability in precipitation, and episodic floods threaten these settlements, leading to highly manipulated hydrologic systems.

The degree of hydrological alteration and consequent ecological change is typically much greater in Mediterranean-climate rivers than humid-climate systems. Dams, diversions, irrigation channels, storage and distribution facilities simultaneously restrict flow regimes, support economic development and destroy the native biological communities in Mediterranean drainage basins. Overcoming the complex relationships among climate, economy and our entangled legal and political institutions challenge the restoration potential of Mediterranean-climate river systems worldwide.

A Fresh Perspective for Managing Water in California: Insights from Applying the European Water Framework Directive to the Russian River

Thu, 3 Apr 2008 00:00:00 +0000

Throughout the world there is increasing public awareness of the importance of sustainable water management to meet both growing human demands and ecosystem needs. Predictions of increased climate variability and indicators of ecological and water quality deterioration have made water management a salient political issue, particularly in arid climate regions such as western North America and the Iberian Peninsula. In recent years, substantial effort has been focused on adopting sustainable water use practices and mitigating the impacts to natural rivers and streams resulting from human activities. Yet the restoration of natural biological communities has been more difficult than anticipated. Our inability to effectively restore and protect rivers and groundwater sources are in part due to the scale of environmental damage inflicted upon them, but also are a consequence of the legal and institutional frameworks under which water is managed. Assessments of the current state of...