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Eleanor R. Griffin

Publications and source records attributed to Eleanor R. Griffin.

13 recordsLinked to original sources
USGS2017

Decreased runoff response to precipitation, Little Missouri River Basin, northern Great Plains, USA

High variability in precipitation and streamflow in the semiarid northern Great Plains causes large uncertainty in water availability. This uncertainty is compounded by potential effects of future climate change. We examined historical variability in annual and growing season precipitation, temperature, and streamflow within the Little Missouri River Basin and identified differences in the runoff response to precipitation for the period 1976-2012 compared to 1939-1975 ( n = 37 years in both cases). Computed mean values for the second half of the record showed little change (<5%) in annual or growing season precipitation, but average annual runoff at the basin outlet decreased by 22%, with 66% of the reduction in flow occurring during the growing season. Our results show a statistically significant ( p < 0.10) 27% decrease in the annual runoff response to precipitation (runoff ratio). Surface-water withdrawals for various uses appear to account for <12% of the reduction in average annual flow volume, and we found no published or reported evidence of substantial flow reduction caused by groundwater pumping in this basin. Results of our analysis suggest that increases in monthly average maximum and minimum temperatures, including >1°C increases in January through March, are the dominant driver of the observed decrease in runoff response to precipitation in the Little Missouri River Basin.

Montana, North Dakota, South Dakota, Wyoming↗
USGS2017

Management of plains cottonwood at Theodore Roosevelt National Park, North Dakota

Establishment of cottonwood trees is driven by flood-induced channel migration, which provides the new surfaces necessary for successful germination and survival. Along the Little Missouri River the largest floods typically result from snowmelt in March or April. Seed release occurs in early summer, and seedlings usually germinate in moist, open locations on point bars at relatively low elevations above the channel. Subsequent channel migration allows seedlings to mature by protecting them from scour in floods and ice jams. Management actions that decrease channel movement will reduce cottonwood reproduction. Growth and survival of cottonwood trees are strongly decreased by extreme low flows. As a result, management activities that decrease low flows could strongly reduce growth or kill trees. Surface-flow diversions are less damaging to trees if carried out during the spring when flows are relatively high. Herbicide application by helicopter to control leafy spurge appears to have inadvertently damaged or killed about 25% of the cottonwood forest along the Little Missouri River in the South Unit. Area of adult trees sprayed has been reduced since 2007 to limit this damage. It is not known whether spraying of cottonwood seedlings on unforested point bars is reducing cottonwood reproduction in the South Unit. Warmer temperatures since 1976 have reduced flood peaks and the ice jamming that magnifies those peaks; as a result channel movement, cottonwood establishment and cottonwood growth have decreased. Increasing temperatures associated with global climate change could continue this trend.

Montana, North Dakota, South Dakota, Wyoming↗
USGS2016

Contributions of moderately low flows and large floods to geomorphic change in the Rio Puerco Arroyo, New Mexico

Abstract—From the mid-1800s to around 1930, monsoonal floods incised an arroyo roughly 100 m wide and 10 m deep along the lower Rio Puerco, NM, from the confluence with the Rio San Jose downstream to the mouth at the Rio Grande, causing sedimentation and flooding downstream. Since the 1930s, the channel has greatly narrowed, a densely vegetated floodplain has developed, the arroyo has partly filled, and downstream sedimentation has greatly decreased. Application of herbicide to a 12-km reach of the arroyo in 2003 to control non-native saltcedar (Tamarix spp.) prompted ongoing studies of channel change in the presence and absence of dense, riparian, woody vegetation. We used digital terrain models and satellite imagery to quantify changes in channel width and location in the sprayed reach and in an unsprayed reach downstream during a moderately low-flow interval (November 2006 to March 2010) and during an interval with a large flood (March 2010 to January/February 2014). Channel width increased in magnitude and variability in the sprayed reach but not in the unsprayed reach over both intervals, continuing a pattern first observed in an earlier study of the period 2003 to 2006. Since the herbicide application in 2003, there have been a total of five meander cutoffs in the sprayed reach and none in the unsprayed reach. In kilometer-long sections of the sprayed reach, channel width is now approaching that at the beginning of the period of channel narrowing in 1935.

New Mexico↗
USGS2015

Alternative standardization approaches to improving streamflow reconstructions with ring-width indices of riparian trees

Old, multi-aged populations of riparian trees provide an opportunity to improve reconstructions of streamflow. Here, ring widths of 394 plains cottonwood (Populus deltoids, ssp. monilifera) trees in the North Unit of Theodore Roosevelt National Park, North Dakota, are used to reconstruct streamflow along the Little Missouri River (LMR), North Dakota, US. Different versions of the cottonwood chronology are developed by (1) age-curve standardization (ACS), using age-stratified samples and a single estimated curve of ring width against estimated ring age, and (2) time-curve standardization (TCS), using a subset of longer ring-width series individually detrended with cubic smoothing splines of width against year. The cottonwood chronologies are combined with the first principal component of four upland conifer chronologies developed by conventional methods to investigate the possible value of riparian tree-ring chronologies for streamflow reconstruction of the LMR. Regression modeling indicates that the statistical signal for flow is stronger in the riparian cottonwood than in the upland chronologies. The flow signal from cottonwood complements rather than repeats the signal from upland conifers and is especially strong in young trees (e.g. 5&ndash;35 years). Reconstructions using a combination of cottonwoods and upland conifers are found to explain more than 50% of the variance of LMR flow over a 1935&ndash;1990 calibration period and to yield reconstruction of flow to 1658. The low-frequency component of reconstructed flow is sensitive to the choice of standardization method for the cottonwood. In contrast to the TCS version, the ACS reconstruction features persistent low flows in the 19th century. Results demonstrate the value to streamflow reconstruction of riparian cottonwood and suggest that more studies are needed to exploit the low-frequency streamflow signal in densely sampled age-stratified stands of riparian trees.

Montana, North Dakota, Soutb Dakota, Wyoming↗
USGS2015

Processes limiting depth of arroyo incision: Examples from the Rio Puerco, New Mexico

We examined channel flow and suspended sediment transport processes within the lower Rio Puerco arroyo, located in semi-arid north-central New Mexico, in an attempt to answer the question: Why did arroyo incision stop by about 1936? Channel flow model results show that in the narrow, incised channel of 1936, the boundary shear stress during a large flood was highest over the lower banks and bank toes, causing a higher potential for erosion of these surfaces than of the channel bed. This would have caused the channel (and arroyo) to widen, and the higher sediment fluxes from those surfaces would have inhibited the capacity of the flow to erode the bed. We found that volumes of sediment delivered to the channel from local erosion of the arroyo wall did not exceed the capacity of the flow to transport sediment, including sand, in suspension. However, sediment supplied from erosion upstream of our study reach may have reduced the capacity of the flow to erode the bed. Our results suggest that arroyo incision ended with the observed reduction in flood peak magnitude, frequency, and duration after 1941.

Conference Paper↗
USGS2014

Processes of arroyo filling in northern New Mexico, USA

We documented arroyo evolution at the tree, trench, and arroyo scales along the lower Rio Puerco and Chaco Wash in northern New Mexico, USA. We excavated 29 buried living woody plants and used burial signatures in their annual rings to date stratigraphy in four trenches across the arroyos. Then, we reconstructed the history of arroyo evolution by combining trench data with arroyo-scale information from aerial imagery, light detection and ranging (LiDAR), longitudinal profiles, and repeat surveys of cross sections. Burial signatures in annual rings of salt cedar and willow dated sedimentary beds greater than 30 cm thick with annual precision. Along both arroyos, incision occurred until the 1930s in association with extreme high flows, and subsequent filling involved vegetation development, channel narrowing, increased sinuosity, and finally vertical aggradation. A strongly depositional sediment transport regime interacted with floodplain shrubs to produce a characteristic narrow, trapezoidal channel. The 55 km study reach along the Rio Puerco demonstrated upstream progression of arroyo widening and filling, but not of arroyo incision, channel narrowing, or floodplain vegetation development. We conclude that the occurrence of upstream progression within large basins like the Rio Puerco makes precise synchrony across basins impossible. Arroyo wall retreat is now mostly limited to locations where meanders impinge on the arroyo wall, forming hairpin bends, for which entry to and exit from the wall are stationary. Average annual sediment storage within the Rio Puerco study reach between 1955 and 2005 was 4.8 &times; 10 5 t/yr, 16% of the average annual suspended sediment yield, and 24% of the long-term bedrock denudation rate. At this rate, the arroyo would fill in 310 yr.

New Mexico↗
USGS2014

Effects of woody vegetation on overbank sand transport during a large flood, Rio Puerco, New Mexico

Distributions of woody vegetation on floodplain surfaces affect flood-flow erosion and deposition processes. A large flood along the lower Rio Puerco, New Mexico, in August 2006 caused extensive erosion in a reach that had been sprayed with herbicide in September 2003 for the purpose of saltcedar ( Tamarix spp.) control. Large volumes of sediment, including a substantial fraction of sand, were delivered to the reach downstream, which had not been treated with herbicide. We applied physically based, one-dimensional models of flow and suspended-sediment transport to compute volume concentrations of sand in suspension in floodplain flow at a site within the sprayed reach and at a site downstream from the sprayed reach. We computed the effects of drag on woody stems in reducing the skin friction shear stress, velocity of flow, and suspended-sand transport from open paths into patches of dense stems. Total flow and suspended-sand fluxes were computed for each site using well-constrained flood-flow depths, water-surface slopes, and measured shrub characteristics. Results show that flow in open paths carried high concentrations of sand in suspension with nearly uniform vertical distributions. Drag on woody floodplain stems reduced skin friction shear stresses by two orders of magnitude, yet sufficient velocities were maintained to transport sand more than 50 m into fields of dense, free-surface-penetrating stems. An increase in shrub canopy extent from 31% in the sprayed reach site to 49% in the downstream site was found to account for 69% of the computed decrease in discharge between the two sites. The results demonstrate the need to compute the spatial distribution of skin friction shear stress in order to effectively compute suspended-sand transport and to predict the fate of sediment and contaminants carried in suspension during large floods.

New Mexico↗
USGS2014

Mummy Lake: An unroofed ceremonial structure within a large-scale ritual landscape

The structure at Mesa Verde National Park known historically as Mummy Lake and more recently as Far View Reservoir is not part of a water collection, impoundment, or redistribution system. We offer an alternative explanation for the function of Mummy Lake. We suggest that it is an unroofed ceremonial structure, and that it serves as an essential component of a Chacoan ritual landscape. A wide constructed avenue articulates Mummy Lake with Far View House and Pipe Shrine House. The avenue continues southward for approximately 6 km where it apparently divides connecting with Spruce Tree House and Sun Temple/Cliff Palace. The avenue has previously been interpreted as an irrigation ditch fed by water impounded at Mummy Lake; however, it conforms in every respect to alignments described as Chacoan roads. Tree-ring dates indicate that the construction of Spruce Tree House and Cliff Palace began about A.D. 1225, roughly coincident with the abandonment of the Far View community. This pattern of periodically relocating the focus of an Anasazi community by retiring existing ritual structures and linking them to newly constructed facilities by means of broad avenues was first documented by Fowler and Stein (1992) in Manuelito Canyon, New Mexico. Periods of intense drought appear to have contributed to the relocation of prehistoric Native Americans from the Far View group to Cliff Palace/Spruce Tree House in the mid-13th century and eventually to the abandonment of all Anasazi communities in southwestern Colorado in the late-13th century.

Journal of Archaeological Science↗
USGS2013

Effects of riparian vegetation on topographic change during a large flood event, Rio Puerco, New Mexico, USA

The spatial distribution of riparian vegetation can strongly influence the geomorphic evolution of dryland rivers during large floods. We present the results of an airborne lidar differencing study that quantifies the topographic change that occurred along a 12 km reach of the Lower Rio Puerco, New Mexico, during an extreme event in 2006. Extensive erosion of the channel banks took place immediately upstream of the study area, where tamarisk and sandbar willow had been removed. Within the densely vegetated study reach, we measure a net volumetric change of 578,050 ± ∼ 490,000 m 3 , with 88.3% of the total aggradation occurring along the floodplain and channel and 76.7% of the erosion focusing on the vertical valley walls. The sediment derived from the devegetated reach deposited within the first 3.6 km of the study area, with depth decaying exponentially with distance downstream. Elsewhere, floodplain sediments were primarily sourced from the erosion of valley walls. Superimposed on this pattern are the effects of vegetation and valley morphology on sediment transport. Sediment thickness is seen to be uniform among sandbar willows and highly variable within tamarisk groves. These reach-scale patterns of sedimentation observed in the lidar differencing likely reflect complex interactions of vegetation, flow, and sediment at the scale of patches to individual plants.

New Mexico↗
USGS2010

Progression of stream bank erosion dudring a large flood, Rio Puerco, New Mexico

In August 2006, a large flood following saltcedar control efforts through a 12-km long segment of the Rio Puerco arroyo resulted in extensive lateral erosion of the streambanks. Almost all woody vegetation on the floodplain and channel banks had been killed by aerial spraying with herbicide in September 2003. During the flood, dead woody bank stems were either removed by the >4-m-deep flood flow or flattened against the bank, eliminating the source of drag that would have protected the banks from erosion. Owing to downstream variation in the shear stresses on the channel banks and floodplain, lateral erosion of the channel banks was highly variable within the sprayed reach, but channel width increased by an average of 84%. Locations and magnitudes of channel bank erosion were documented from high-resolution imagery and a post-flood (January 2007) high-precision Global Positioning System survey. Topographic data collected during the January 2007 field survey combined with geomorphic mapping from imagery provided a means to infer the progression and relative timing of bank erosion during the flood. Observations and calculations indicate channel widening resulted from a combination of direct fluvial erosion of the lower banks and mass failures of the upper banks. Applications of physically based models of flow and sediment transport demonstrate the relative influence of local floodplain slope, arroyo topography, and orientation of the channel centerline relative to the down-valley axis on bank erosion. Differences in suspended sand concentrations computed using model-calculated “skin friction” shear stress quantify the erosion rate at a site where channel width doubled during the flood.

Conference Paper↗