Comparing catchment hydrologic response to a regional storm using specific conductivity sensors

Abstract

A better understanding of stormwater generation and solute sources is needed to improve the protection of aquatic ecosystems, infrastructure, and human health from large runoff events. Much of our understanding of water and solutes produced during stormflow comes from studies of individual, small headwater catchments. This study compared many different types of catchments during a single large event to help isolate landscape controls on streamwater and solute generation, including human‐impacted land cover. We used a distributed network of specific electrical conductivity sensors to trace storm response during the post‐tropical cyclone Sandy event of October 2012 at 29 catchments across the state of New Hampshire. A citizen science sensor network, Lotic Volunteer for Temperature, Electrical Conductivity, and Stage, provided a unique opportunity to investigate high‐temporal resolution stream behavior at a broad spatial scale. Three storm response metrics were analyzed in this study: (a) fraction of new water contributing to the hydrograph; (b) presence of first flush (mobilization of solutes during the beginning of the rain event); and (c) magnitude of first flush. We compared new water and first flush to 64 predictor attributes related to land cover, soil, topography, and precipitation. The new water fraction was positively correlated with low and medium intensity development in the catchment and riparian buffers and with the precipitation from a rain event 9 days prior to Sandy. The presence of first flush was most closely related (positively) to soil organic matter. Magnitude of first flush was not strongly related to any of the catchment variables. Our results highlight the potentially important role of human landscape modification in runoff generation at multiple spatial scales and the lack of a clear role in solute flushing. Further development of regional‐scale in situ sensor networks will provide better understanding of stormflow and solute generation across a wide range of landscape conditions.

Controls of Chloride Loading and Impairment at the River Network Scale in New England

“…A network of in situ, high‐frequency sensors characterized specific conductance in streams, rivers, and storm drainage infrastructure in diverse land cover throughout New Hampshire, eastern Massachusetts, and western Maine (Contosta et al, 2017; Inserillo et al, 2017). The Lotic Volunteers Temperature, Electrical Conductivity, and Stage (LoVoTECS) network collected data throughout the study region from 2011 to 2016.…”

Runoff Response to Soil Moisture and Micro-topographic Structure on the Plot Scale

“…Furthermore, the threshold value chosen should not be limited by the volumetric soil moisture content. While our research used the relative saturation index based on HOF theory, other parameters, such as hydraulic conductivity, might be more reasonable 41,42,50,51 . However, the methods mentioned above should be tested and verified in future research initiatives, which are beyond the scope of the current study.…”

Effects of Reforestation of a Degraded Imperata Grassland on Dominant Flow Pathways and Streamflow Responses in Leyte, the Philippines

“…Because rainfall EC data were not available for each individual event, an average EC of 8 μS/cm was used in the computations for all events (range: 3–20 μS/cm; EC < 10 μS/cm for 16 out of 18 samples). Several recent studies have shown that, despite not being a conservative tracer, EC can be useful for hydrograph separation (Inserillo et al, ; Pellerin et al, ; Robinson et al, ). However, other studies have shown that there can be substantial differences between EC‐ and isotope‐based hydrograph separation results for some events (Litt et al, ; Penna et al, ).…”