The staying power of perceptions in a dynamic system : a longitudinal stakeholder analysis in the Yellowstone River Valley

Understanding how stakeholders conceptualize the dynamic environmental systems they live within and act upon is essential for long-term sustainability planning. For shared resource systems where decision making is increasingly democratized, agencies engage stakeholders to document local understandings of physical processes useful for resource management. For a variety of fiscal, logistical, and policy reasons, most studies are snapshots in time with few agencies able to devote resources for longitudinal studies. Yet for large river systems that regularly change with floods, drought, and floodplain development cycles, one-off social studies are unable to respond to such human- environment dynamism. To explore longitudinal human-water dynamics in the Yellowstone River reach in Montana (US), this study uses interviews with 15 individuals interviewed in 2006, 2012, and 2018 field seasons. The Yellowstone River is the largest undammed river in the US. It is located in the arid Western United States, and experiences annual flooding from mountain snowmelt, regular drought cycles, increased water use from floodplain development, irrigation, and recreation. Interviewees had a history of involvement with the Yellowstone River decision making and/or were riverfront landowners each with the capacity to shape the physical features of this system. This study takes a scholarly approach to expressed participant concerns as empirical evidence that reflects the socio-hydrological phenomenon occurring in the Yellowstone River Valley. Analysis of stakeholder accounts of physical processes pay special attention to expressions of how they understand the physical processes (flood, drought, and erosion) and how they express it should be managed. The benefit of engaging the same stakeholders with the same questions in 2006, 2012, and 2018 affords attention to any patterns of change over time concerning stakeholders' descriptions of riverine processes. Ultimately, this study brings clarity to the place-based phenomenon taking place in t Yellowstone River through a longitudinal comparative analysis.

Terraces of the Ohře River in Žatec Area, Czech Republic: When Models of Holocene Fluvial Development Are Not Sufficient

The development of the Ohře River near Žatec between the Late Glacial Maximum (LGM) and present time was studied to obtain its natural trajectory and thus to understand the role of human impact on floodplain development. The study was based on geomorphic research, sampling and dating fluvial sediments by optically stimulated luminescence (OSL) and anthropogenic contamination by Sn since 16th century. During the LGM and the Pleistocene/Holocene transition (P/H), the river valley was shaped by large, incising meanders creating the entire valley floor. The Holocene river, due to decreased channel forming discharges, only slowly continued the LGM and P/H trajectory by cut-offs of the large palaeomeander necks and channel belt narrowing and incision. The last Holocene incision step was likely triggered by hydrological extremes of the Little Ice Age. The LGM and P/H Ohře River consequently changed from meandering to low sinuous, incised in the valley floor; this incision was completed by river engineering in the 20th century. The Ohře River development can thus be rationalised neither by traditional terrace-step formation model nor by model of the Anthropogenic aggradation.

The FLOod Probability Interpolation Tool (FLOPIT): A Simple Tool to Improve Spatial Flood Probability Quantification and Communication

Understanding flood probabilities is essential to making sound decisions about flood-risk management. Many people rely on flood probability maps to inform decisions about purchasing flood insurance, buying or selling real-estate, flood-proofing a house, or managing floodplain development. Current flood probability maps typically use flood zones (for example the 1 in 100 or 1 in 500-year flood zones) to communicate flooding probabilities. However, this choice of communication format can miss important details and lead to biased risk assessments. Here we develop, test, and demonstrate the FLOod Probability Interpolation Tool (FLOPIT). FLOPIT interpolates flood probabilities between water surface elevation to produce continuous flood-probability maps. FLOPIT uses water surface elevation inundation maps for at least two return periods and creates Annual Exceedance Probability (AEP) as well as inundation maps for new return levels. Potential advantages of FLOPIT include being open-source, relatively easy to implement, capable of creating inundation maps from agencies other than FEMA, and applicable to locations where FEMA published flood inundation maps but not flood probability. Using publicly available data from the Federal Emergency Management Agency (FEMA) flood risk databases as well as state and national datasets, we produce continuous flood-probability maps at three example locations in the United States: Houston (TX), Muncy (PA), and Selinsgrove (PA). We find that the discrete flood zones generally communicate substantially lower flood probabilities than the continuous estimates.

THE NEW-FOUND OLD RUS SITES ON THE LOWER TETERIV RIVER BASIN

The paper is the brief description of the Old Rus sites situated on the Lower Teteriv River banks. Still recently that area was one of the poor studied regions of the Kyiv Polissia area. According to the 19th century sources there were 2 medieval hill-forts here. 13 settlements of the 10th—13th centuries were found on the territory of Ivankiv region in the 20th century. During the last decade the authors and other researchers have inspected 15 of the 22 settlements known in that area. The most of them were discovered first. The ceramics of the 10th—13th centuries, iron slag, domestic and production artifacts (iron knife, stone spindle whorl and millstone) were found on these settlements. More than half of them (12 ones) have been found on the uplands of the Teteriv and Zdvizh floodplains that hold the promise of the medieval sites at other locations of the river valleys. The researchers of the second half of 20th century considered that settlements on the river’s valleys were seasonal sites of the metallurgists and herders. The square of the found floodplain settlements and the number and characteristics of the finds indicate the different conditions of their functioning and purposes. They can be preliminarily divided into 3 groups. The traditional settlements with permanent inhabitants belong to the first group. They are of largest sizes compared to other floodplain settlements. Another group includes so-called seasonal settlements. The population of these sites (or their part) occupied the site after high water and lived until autumnal cold weather. The both groups probably could be of production character. The sites occupying small areas (mainly about 1000 m2) with a little number of ceramics represent the third group. Perhaps they were associated with production activity on floodplains. People who were given temporary employment of shepherds or fishermen could live there. The proposed classification of the Old Rus floodplain settlements is pretty conditional because it is based on such indications and characteristics as sizes, quantity of ceramics found etc., obtained during archaeological survey. Ceramics of these sites dated both to the 10th—11th and the 12th—13th centuries that testifies to further floodplain development and appearance of the new settlements.

The Risky Business of Flood Control

This chapter discusses flood control policy, recounting how Frank Townend—who had been the civil defense director for Luzerne County, Pennsylvania, for over a decade when Hurricane Agnes struck—ignored the warnings coming from the National Weather Service. He was sure that the dikes could hold back the Susquehanna River. Convinced that the levees would protect the city, he did not order an evacuation of Wilkes-Barre before flooding began. In the hours before the Agnes-induced flooding, officials reassured the public that they would stay safe and dry behind their protective flood walls, but they soon found themselves and their property in peril. The tragedy is that while residents of the cities were unaware they were at risk, for many years scholars had been warning that structural barriers to flooding were not flood proof and instead encouraged risky behavior in river valleys. The floodwalls lulled people into believing they could safely build residences and businesses on the river's natural floodplain. Disaster scholars use the term “moral hazard” to describe government policy that increases public risk taking. Dikes and levees along the Susquehanna became a moral hazard because once they had been installed, local officials encouraged floodplain development to maximize land use and increase local tax revenues.

Large wood and stream longitudinal disconnectivity

<p>Large wood historically influenced diverse geomorphic and ecological processes in channels from first-order streams to major rivers. Centuries of deforestation and wood removal from channels have significantly reduced the presence of wood. The presence of large wood tends to decrease longitudinal connectivity, but increases lateral and vertical connectivity that arises from the presence of wood as an obstacle in the channel. Channel-spanning logjams, in particular, enhance vertical connectivity via hyporheic exchange flow and lateral connectivity via overbank flow, channel avulsion, lateral channel migration, or formation of secondary channels. In mountain streams, these effects are likely to be more pronounced in relatively wide, low gradient reaches with thicker alluvium and greater space for floodplain development and channel lateral mobility. River restoration increasingly includes maintaining or reintroducing large wood to channels, but there are relatively few studies that can be used to constrain management targets by providing data on instream large wood loads in unmanaged streams in diverse geographic settings. Here, we document the longitudinal distribution and persistence of logjams in the US Southern Rocky Mountains over a period of a decade. Key results include: (1) The longitudinal distribution of logjams varies significantly between successive stream reaches. Reaches are hundreds to thousands of meters in length and defined based on consistent stream gradient and channel lateral confinement. (2) Individual logjams change on an annual basis and typically persist less than a decade, although new logjams form frequently. (3) Individual logjams are more persistent in wide, low gradient reaches. (4) The population of logjams within a reach is more resilient to major floods in wide, low gradient reaches. The continuing breakup of jams and formation of new jams underscores the importance of ongoing wood recruitment in a natural river corridor. The results also imply that large wood reintroduction may be most effectively focused on specific types of wood process domains where the persistence and geomorphic effects of large wood are enhanced.</p>

Explaining the pitfalls of quantifying population in riverine floodplains using Nighttime Light

<p>Flooding is globally one of the most damaging natural hazards. Flood risk will most likely increase in the near future due to increases in flood frequency attributed to climate change and growth in population and wealth in flood prone areas. This growth in wealth and population is increasingly considered as a major driver for the increase in flood losses in the last decades. Floodplains are susceptible to floods, but historically people have always been settling in floodplains. The growth of population in floodplains, which is a substantial cause for increased flood risk, is essential to consider for decision making in floodplain development, as improper development increases flood exposure and aggravates flood risk. The science of socio-hydrology tries to capture the interaction between humans and floods in the floodplain, but it is necessary to identify these mechanisms on a broader scale. A way of doing this, is to look at the development of floodplain population density over the years, but population data is not available on a long temporal scale. Therefore, Nighttime light data was used to model the gaps in the availability of population data. Nighttime light data captures the illumination on earth and is available on a large temporal and spatial scale. It also has a high correlation with population data. However, the relationship between Nighttime light data and population data is not straightforward. This study tries to model a population proxy using Nighttime light data and explains when and why it does or does not work. Validation of the model shows that in some regions the predicted data is relatively precise, but ultimately, due to the lack of data, the accuracy is unknown. This study shows that understanding the behavior of NTL is valuable, because it has the potential to map Socio-Economic variables in data-scarce areas.</p>