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As human interactions with Earth systems continue to intensify, understanding the complex relationships among human activity, landscape change, and societal responses to those changes becomes increasingly important. Interdisciplinary research centered on the theme of “feedbacks” in human–landscape systems serves as a promising focus for unraveling these interactions. This paper examines the specific case of the 2012 Waldo Canyon Fire of Colorado, where human responses after the fire to perceived threats of hydro-geomorphological hazards included construction of tall fences at the base of a burned watershed. These actions prompted feedbacks that promoted further landscape change that ultimately increased those hazards, rather than dampening the hydro-geomorphological effects of fire. Geomorphic analysis showed that the fences trapped particles that would naturally move through the system by flows with recurrence intervals greater than 3.3 years. With the particles blocked by the fences, the channel downstream became erosive, because it was devoid of large particles that produce substantial hydraulic resistance. Channel incision prompted a second human response to pave the eroding channel, which led to further incision downstream. This cycle of positive feedbacks between human decision-making and landscape change eventually led to a complete channelization of the stream channel downstream of the fences. The explanation for the transformation of the post-fire landscape therefore lies in the interacting human impacts and feedbacks, rather than the expected post-fire hydro-geomorphological adjustments. An initial agent-based model, capable of integrating social and hydro-geomorphological data, simulates these interacting impacts and feedbacks. Further refinement with more complete data input, especially pertaining to human decision making at individual or local levels, is required to fully demonstrate the utility and promise of this tool for application to geomorphic analysis. [ABSTRACT FROM AUTHOR]

The US Gulf of Mexico coastal region has repeatedly been subjected to major flood events. Local geotechnical site characteristics and geomorphology can change due to sediment transport processes during such events. However, field measurements during extreme conditions are challenging. This paper discusses initial attempts at a combined geotechnical and geophysical site investigation of the uppermost layers of riverbeds following severe flooding events at three different rivers in Texas: the Guadalupe, Brazos, and Colorado Rivers in terms of sediment strength derived from a portable free fall penetrometer, backscatter intensity recorded by a chirp sonar, and soil sample characterization. Results show low strength sediments (<40 kPa) along the investigated sections of the Guadalupe and Brazos riverbanks. Although sediments in the center of the Brazos River were characterized with higher strength (>50 kPa) and larger grain sizes (d 50 ∼ 0.3 mm), sediment strength of the Guadalupe and Colorado Rivers displayed more variations around bridge piers. The spatial variations likely resulted from sediment remobilization processes and local scour under severe hydrodynamic conditions. Both, geotechnical and geophysical results, reflected the observed variations in the riverbed sediments; nonetheless, a quantitative correlation among the rivers was impeded by challenges primarily related to limitations of spatial accuracy and the significant riverbed heterogeneity, as well as shallow water limitations of the chirp sonar. • Combined geotechnical and geophysical site characterization at three Texas river sections • Measurements from small vessels and in areas of unknown riverbed conditions • Sediment dynamics were reflected in geotechnical and geophysical data • Qualitative relationship between portable free fall penetrometer and chirp sonar • Three river sections differed significantly in local sediment properties [ABSTRACT FROM AUTHOR]

Prehistoric peoples chose farming locations based on environmental conditions, such as soil moisture, which plays a crucial role in crop production. Ancestral Pueblo communities of the central Mesa Verde region became increasingly reliant on maize agriculture for their subsistence needs by AD 900. Prehistoric agriculturalists (e.g., Ancestral Pueblo farmers) were dependent on having sufficient soil moisture for successful plant growth. To better understand the quality of farmland in terms of soil moisture, this study develops a static geospatial soil moisture model, the Soil Moisture Proxy Model, which uses soil and topographic variables to estimate soil moisture potential across a watershed. The model is applied to the semi-arid region of the Goodman watershed in the central Mesa Verde region of southwestern Colorado. We evaluate the model by comparing the Goodman watershed output to two other watersheds and to soil moisture sensor values. The simple framework can be used in other regions of the world, where water is also an important limiting factor for farming. The general outcome of this research is an improved understanding of potential farmland and human-environmental relationships across the local landscape. [ABSTRACT FROM AUTHOR]