Geology topics

Research about Bill Williams River

Source-linked reports with geographic coverage including Bill Williams River.

5 recordsLinked to original sources

USGS2016

Managing water and riparian habitats on the Bill Williams River with scientific benefit for other desert river systems

This report details modeling to: 1) codify flow-ecology relationships for riparian species of the Bill Williams River as operational guidance for water managers, 2) test the guidance under different climate scenarios, and 3) revise the operational guidance as needed to address the effects of climate change. Model applications detailed herein include the River Analysis System (HEC-RAS) and the Ecosystem Functions Model (HEC-EFM), which was used to generate more than three million estimates of local seedling recruitment areas. Areas were aggregated and compared to determine which scenarios generated the most seedling area per unit volume of water. Scenarios that maximized seedling area were grouped into a family of curves that serve as guidance for water managers. This work has direct connections to water management decision-making and builds upon and adds to the rich history of science-based management for the Bill Williams River, Arizona, USA.

Arizona↗

USGS2014

Abandoned floodplain plant communities along a regulated dryland river

Rivers and their floodplains worldwide have changed dramatically over the last century because of regulation by dams, flow diversions and channel stabilization. Floodplains no longer inundated by river flows following dam-induced flood reduction comprise large areas of bottomland habitat, but the effects of abandonment on plant communities are not well understood. Using a hydraulic flow model, geomorphic mapping and field surveys, we addressed the following questions along the Bill Williams River, Arizona: (i) What per cent of the bottomland do abandoned floodplains comprise? and (ii) Are abandoned floodplains quantitatively different from adjacent xeric and riparian surfaces in terms of vegetation composition and surface sediment? We found that nearly 70% of active channel and floodplain area was abandoned following dam installation. Abandoned floodplains along the Bill Williams River tend to be similar to each other yet distinct from neighbouring habitats: they have been altered physically from their historic state, leading to distinct combinations of surface sediments, hydrology and plant communities. Abandoned floodplains may transition to xeric communities over time but are likely to retain some riparian qualities as long as there is access to relatively shallow ground water. With expected increases in water demand and drying climatic conditions in many regions, these surfaces and associated vegetation will continue to be extensive in riparian landscapes worldwide

Arizona↗

USGS2013

Coupled hydrogeomorphic and woody-seedling responses to controlled flood releases in a dryland river

Interactions among flow, geomorphic processes, and riparian vegetation can strongly influence both channel form and vegetation communities. To investigate such interactions, we took advantage of a series of dam-managed flood releases that were designed in part to maintain a native riparian woodland system on a sand-bed, dryland river, the Bill Williams River, Arizona, USA. Our resulting multiyear flow experiment examined differential mortality among native and nonnative riparian seedlings, associated flood hydraulics and geomorphic changes, and the temporal evolution of feedbacks among vegetation, channel form, and hydraulics. We found that floods produced geomorphic and vegetation responses that varied with distance downstream of a dam, with scour and associated seedling mortality closer to the dam and aggradation and burial-induced mortality in a downstream reach. We also observed significantly greater mortality among nonnative tamarisk (Tamarix) seedlings than among native willow (Salix gooddingii) seedlings, reflecting the greater first-year growth of willow relative to tamarisk. When vegetation was small early in our study period, the effects of vegetation on flood hydraulics and on mediating flood-induced channel change were minimal. Vegetation growth in subsequent years resulted in stronger feedbacks, such that vegetation's stabilizing effect on bars and its drag effect on flow progressively increased, muting the geomorphic effects of a larger flood release. These observations suggest that the effectiveness of floods in producing geomorphic and ecological changes varies not only as a function of flood magnitude and duration, but also of antecedent vegetation density and size.

Arizona↗

USGS2006

Defining ecosystem flow requirements for the Bill Williams River, Arizona

Alteration of natural river flows resulting from the construction and operation of dams can result in substantial changes to downstream aquatic and bottomland ecosystems and undermine the long-term health of native species and communities (for general review, cf. Ward and Stanford, 1995; Baron and others, 2002; Nilsson and Svedmark, 2002). Increasingly, land and water managers are seeking ways to manage reservoir releases to produce flow regimes that simultaneously meet human needs and maintain the health and sustainability of downstream biotaa.

Arizona↗

USGS1998

Establishment of woody riparian vegetation in relation to annual patterns of streamflow, Bill Williams River, Arizona

Previous studies have revealed the close coupling of components of annual streamflow hydrographs and the germination and establishment of Populus species. Key hydrograph components include the timing and magnitude of flood peaks, the rate of decline of the recession limb, and the magnitude of base flows. In this paper, we retrospectively examine establishment of four woody riparian species along the Bill Williams River, Arizona, USA, in the context of annual patterns of streamflow for the years 1993–1995. The four species examined were the native Populus fremontii, Salix gooddingii , and Baccharis salicifolia and the exotic Tamarix ramosissima . We modeled locations suitable for germination of each species along eight study transects by combining historic discharge data, calculated stage-discharge relationships, and seed-dispersal timing observations. This germination model was, a highly significant predictor of seedling establishment. Where germination was predicted to occur, we compared values of several environmental variables in quadrats where we observed successful establishment with quadrats where establishment was unsuccessful. The basal area of mature woody vegetation, the maximum annual, depth to ground water, and the maximum rate of water-table decline were the variables that best discriminated between quadrats with and without seedlings. The results of this study suggest that the basic components of models that relate establishment of Populus spp. to annual patterns of streamflow may also be applicable to other woody riparian species. Reach-to-reach variation in stage-discharge relationships can influence model parameters, however, and should be considered if results such as ours are to be used in efforts to prescribe reservoir releases to promote establishment of native riparian vegetation.

Arizona↗