Mark Lorang

In this research we take a systems ecology approach to the evaluation of river floodplains by ranking them according to their energetic complexity at or near base flow conditions. The underlying hypothesis is that energetic complexity equates to a higher potential for sustaining maximum biological diversity, in particular as it relates to Salmonids. Fr number is a hydraulic index of relative specific energy in a flowing water column ranging from calm, no flow conditions where Fr = 0 to 0.8 at the onset of rapids and higher values approaching 1 or > at locations of breaking waves and hydraulic jumps. Most of the water flowing in a gravel-bed river exists in the transition range of Fr = 0.1 to 0.8, creating a complex array of potential hydrologic habitat commonly described through observation as riffles, runs, pools eddies, and so on. We use 1.6 m2 resolution multispectral satellite imagery to predict and map water depth (h), mean flow velocity (V) and Froude number (Fr=V/(gh)^0.5)...

A multi-scale classification and analysis of floodplain features was used to estimate freshwater habitats for Pacific salmon across the North Pacific Rim (NPR). Riverine habitat classifications were derived at 30 m spatial resolution using multispectral Landsat TM imagery and >60 m resolution digital terrain information encompassing the major NPR rivers. Similar classifications were also derived using relatively fine- scale (i.e.

Satellite (Quickbird II) and airborne (LIDAR, hyperspectral and ultra-high (<10cm) resolution multispectral, and thermal IR) imagery are used to characterize riparian and aquatic habitats of alluvial, gravel-bed river floodplains. Aquatic environments are classified into discrete habitats (e.g., springs, riffles, backwater pools, turbulent runs, eddy pools, etc) by their unique hydraulic character (depth, Froude), channel position, and connectivity composition across the riverscape. Thermal IR provides data of thermal variation and serves as indicators of groundwater-surface water interaction. Riparian forest vegetation is classified by species through supervised classification of pixel-specific reflectance signatures. Vegetation is further separated into age classes for dominant gallery forest species by coupling LIDAR bare-earth DEM and LIDAR first-return metrics to determine canopy height across the vegetation classification. The integration of these various sources of remote ...

The Yakima River system historically produced robust annual runs of chinook, sockeye, chum and coho salmon and steelhead. Many different stocks or life history types existed because the physiography of the basin is diverse, ranging from very dry and hot in the high desert of the lower basin to cold and wet in the Cascade Mountains of the headwaters (Snyder

We are proposing the 22, 515 km2 glacially-sculpted Flathead River Basin located in Montana and British Columbia as a Hydrologic Observatory. This hydrologic landscape is diverse and includes large pristine watersheds, rapidly developing intermountain valleys, and a 95 km2 regulated reservoir and 510 km2 lake. The basin has a topographic gradient of over 2,339 m, and spans high alpine to

ABSTRACT Flathead Lake— the largest freshwater lake in the western USA—undergoes significant short-term water level oscillations due to standing barotropic waves (seiches). Large surface area and several embayments cause high amplitudes and complicated spatial pattern of the seiches. We used water level records from 12 sites distributed around the lake and the results of numerical circulation modeling to establish the modal composition of seiches, the two-dimensional wave shape, and current patterns. For this, we directly applied harmonic analysis to the output of a full circulation model. Compared to the traditional reduced eigenvalue problem, the proposed approach allows modal separation of real datasets that is potentially advantageous for analysis of the resonant response to periodic wind forcing. Surprisingly, both model results and observations demonstrated predominance of the 'two-node' horizontal mode, whereas the usually most acute 'one-node' mode was attenuated by the large shallow bay connected through a narrow straight to the main lake basin. Energy of several higher modes was concentrated around the mouth of the main inflow suggesting their strong effect on the redistribution of the inflow waters and suspended matter within the lake. The rotary spectral analysis revealed rotational character of two particular modes and localized potential upwelling/downwelling areas, where water-sediment matter transport could be intensified by 'seiche pumping'. The results have a wide range of applications including transport of dissolved and suspended matter, assement of shoreline erosion, and exchange processes at the water-sediment boundary. In addition, knowledge of the spatial seiche pattern facilitates estimation of the hypothetical lake response to earthquakes in this seismically active region.

Geomorphic structures and hydrologic dynamics shape the physical template of lotic ecosystems, both on the surface and within the hyporheic zone. While recent studies have described the importance of surface and subsurface habitat diversity, our ongoing field and modeling research projects are documenting the interdependence of channel and hyporheic habitat diversity along with the role of biological processes in responding and contributing to hydrologic complexity and habitat diversity in fluvial landscapes. Patterns of variation in both hydrologic flow paths and water temperature can be used to illustrate the interdependence of complexity and diversity in lotic and hyporheic environments, both of which are mediated by variation in stream geomorphology and discharge regime. For instance, our data suggest that flood-plain topography interacts with the discharge regime to determine the complexity of surface and hyporheic hydrology, which influences and is influenced by seasonal growt...

... In this paper we examine the effect of lake level regulation by contrasting erosion, shoreline retreat and morphological ... Physical effects of lake level regulation 283 Fig. ... steep areas, the entire shoreline of Flathead Lake is dominated by homes and docks, retaining walls and other ...

A series of small dams were built in Icicle Creek in 1937 to facilitate the operations of Leavenworth National Fish Hatchery. However, several of those dams have been abandoned spurring recent discussions among local watershed conservation groups, as well as state and federal agencies, about removing the dams and the potential impact to the lower reaches of Icicle Creek due to elevated sedimentation. The objective of this study was to measure the total volume of sediment trapped behind the Icicle Creek dams and estimate the potential sedimentation impacts for the lower portion of Icicle Creek should the dams be removed. Another objective was to assess the ability of the river to flush the sediments and naturally restore the system to as close to its predam condition as possible. A flow-competence approach was used to assess the restoration potential of the river to do the work of flushing sediments and reestablishing the predam stream channel characteristics. A sediment probe, a total station, a GPS and aerial photographs were used to map out sediment deposits and measure their depths to determine sediment volumes. Grain size distributions from bed sediments, bars, islands and stream banks were used to assess potential downstream sedimentation impacts. The total volume of sediment trapped behind the dams was estimated at 36,000 m3 (± 4000 m3). The river has sufficient stream power to flush these sediments over 90% of its natural discharge regime. Controlled flushing of the trapped sediments over several years poses very little threat to the water quality and spawning habitats in the lower Icicle Creek scaled against natural flux rates.

... have the highest restoration potential and to improve baseline assessment and monitoring. ... Table 1. Error matrix describing the accuracy of the classifications for depth ... low-relief landscapes: Assessing surface water flow impedance using LIDAR-derived digital elevation models. ...