Bonnie Ludka

Cal Poly Humboldt

An equilibrium framework is used to describe the evolution of the cross-shore profile of five beaches (medium grain size sand) in southern California. Elevations were observed quarterly on cross-shore transects extending from the back beach to 8 m depth, for 3-10 years. Transects spaced 100 m in the alongshore direction are alongshore averaged into...

[Temporary link to paper: https://authors.elsevier.com/a/1Wf191M2DU~iLk ] Four southern California beaches were nourished with offshore sand placed as subaerial pads several meters thick, ~50 m wide, and spanning between 500 and 1500 m alongshore. Three nourishments constructed with coarser than native sand, placed in 2012 at Imperial, Cardiff and...

Sustained, quantitative observations of nearshore waves and sand levels are essential for testing beach evolution models, but comprehensive datasets are relatively rare. We document beach profiles and concurrent waves monitored at three southern California beaches during 2001-2016. The beaches include offshore reefs, lagoon mouths, hard substrates,...

Email or send a ResearchGate Message for a copy! Abstract: Beach nourishment — the addition of sand to increase the width or sand volume of the beach — is a widespread coastal management technique to counteract coastal erosion. Globally, rising sea levels, storms and diminishing sand supplies threaten beaches and the recreational, ecosystem, groun...

A moderate-size (344,000 m³) subaerial beach nourishment was placed in 2012 in front of flood-prone homes at Imperial Beach, California. The subaerially persistent coarser-than-native nourishment sand spread alongshore over a ∼4 km span. By winter 2018/19 subaerial sand volumes in front of the flood-prone homes were eroded to near pre-nourishment l...

Sea-level rise (SLR) is and will continue to be a pressing issue in the rural, North Coast region of California, especially since nearby Wigi (or Humboldt Bay) is experiencing one of the fastest rates of relative SLR on the U.S. West Coast. In this paper, we argue that SLR presents a transformative opportunity to rekindle environmental relationship...

Waves overtop berms and seawalls along the shoreline of Imperial Beach (IB), CA when energetic winter swell and high tide coincide. These intermittent, few-hour long events flood low-lying areas and pose a growing inundation risk as sea levels rise. To support city flood response and management, an IB flood warning system was developed. Total water...

Storm wave run-up causes beach erosion, wave overtopping, and street flooding. Extreme runup estimates may be improved, relative to predictions from general empirical formulae with default parameter values, by using historical storm waves and eroded profiles in numerical runup simulations. A climatology of storm wave run-up at Imperial Beach, Calif...

Cross-shore profile response to energetic wave events is challenging to predict because the physics are poorly understood and wave and topographic data are often sparse or unknown. Six events with varying duration, wave intensity and beach slopes are used to calibrate and assess two process-based cross-shore models, CShore and XBeach, at two southe...

Beaches around the world continuously adjust to daily and seasonal changes in wave and tide conditions, which are themselves changing over longer time-scales. Different approaches to predict multi-year shoreline evolution have been implemented; however, robust and reliable predictions of shoreline evolution are still problematic even in short-term...

Widespread erosion associated with energetic waves of the strong 2015–2016 El Niño on the U.S. West Coast has been reported widely. However, Southern California was often sheltered from the northerly approach direction of the offshore waves. The few large swells that reached Southern California were not synchronous with the highest tides. Although...

The El Niño-Southern Oscillation is the dominant mode of interannual climate variability across the Pacific Ocean basin, with influence on the global climate. The two end members of the cycle, El Niño and La Niña, force anomalous oceanographic conditions and coastal response along the Pacific margin, exposing many heavily populated regions to incre...

Wave conditions in Southern California during the 2015-2016 El Niño were similar to the 2009-2010 El Niño, previously the most erosive (minimum beach widths and subaerial sand levels) in a 7 year record. As of February 2016, Torrey Pines Beach had eroded slightly below 2009-2010 levels, threatening the shoulder of a major highway. However, Cardiff,...

A model of the thermocline linearized around a specified stratification and the barotropic linear winddriven Stommel solution is constructed. The forcings are both mechanical (the surface wind stress) and thermodynamical (the surface buoyancy boundary condition). The effects of diapycnal diffusivity and of eddy fluxes of buoyancy, parameterized in...

We present ultraviolet-integrated and azimuthally averaged surface photometric properties of a sample of 44 dwarf irregular (dIm), blue compact dwarf, and Sm galaxies measured from archival near-ultraviolet (NUV) and far-ultraviolet (FUV) images obtained with the Galaxy Evolution Explorer (GALEX). We compare the UV to Halpha and V-band properties a...