Geology topics

Beverley Wemple

Publications and source records attributed to Beverley Wemple.

4 recordsLinked to original sources

USGS2025

Assessing and enhancing national water model streamflow predictions for montane catchments in the northeastern United States

This study evaluates National Water Model (NWM) performance in low-order montane catchments across the northeastern United States by comparing retrospective simulations to measured observations. To address deficiencies, we develop a machine learning (ML) correction model for selected sites using LightGBM, a different approach from conventional bias correction methods. Montane, low-order streams play a crucial role in water quality and flood generation but pose challenges for streamflow prediction and are under-represented in the national streamgaging network. NWM provides streamflow forecasts across the United States; yet a focused assessment of its performance in these settings has not been comprehensively undertaken. Results indicate NWM performance varied seasonally, with the best performance during the fall and particularly poor performance during snowmelt, spring runoff, and high flow events, with a tendency towards flow underestimation. The ML correction model markedly improved hourly streamflow prediction accuracy based on continuous time series and runoff event-based metrics. Including antecedent water level measurements as input, even from distant sites, greatly improved model performance, demonstrating the potential to improve predictions by deploying supplemental low-cost water level sensors. We demonstrate that NWM performance can be improved in these complex watersheds using ML tools. This approach could be implemented elsewhere to improve NWM streamflow predictions.

Maine, Massachusetts, New Hampshire, New York, Pen↗

USGS2025

Warmer winters drive declines in snowpack and consequent increases in annual and seasonal runoff in a headwater region of the northeastern United States

In montane, snow-affected regions of the United States (US), a warming climate threatens the timing and amount of future water delivery. It is expected that winter precipitation falling as snow will continue decreasing and the frequency of winter snowmelt events will continue increasing, with unknown impacts on partitioning of water between evapotranspiration and runoff, water quality, flooding, and drought. The Northeastern US represents a humid environment with relatively uniform precipitation seasonality and a transient snowpack, and the region has been largely overlooked with respect to changing winter conditions and water availability, in part due to scarce observations. An observational network has been recently established to span a Summit-to-Shore (S2S) continuum in Vermont for improved understanding and characterization of snowpack variability across the landscape. We leverage the S2S network alongside available multi-decade records of meteorology, snow depth, and runoff to relate long-term snowpack characteristics in the Northeast to seasonal and annual runoff within the high-elevation headwater Ranch Brook watershed (9.6 km2). In the last 57 years, average winter temperatures have increased by 2.6oC, snow season length has decreased by almost 3 weeks, average snow water equivalent has decreased by 13%, and winter season rain-on-snow (ROS) event frequency has increased from 1 to 3.5 per year. In response, average daily winter season runoff has increased, which is strongly related to increased annual runoff ratios (R2 = 0.70). Separating the 22-year runoff record into years with more versus less winter season runoff, years with more winter runoff corresponded to significantly increased winter temperatures, 15% smaller snowpack, two times more ROS events, 52% more winter runoff, 31% larger annual runoff ratio, and increased summer rainfall variance. A steady decline in the regional snowpack and related impacts on downstream water resources implications for ecosystems and agricultural, industrial, and domestic water supply.

Vermont↗

USGS2019

Influence of land use and hydrologic variability on seasonal dissolved organic carbon and nitrate export: Insights from a multi-year regional analysis for the northeastern USA

Land use/land cover (LULC) change has significant impacts on nutrient loading to aquatic systems and has been linked to deteriorating water quality globally. While many relationships between LULC and nutrient loading have been identified, characterization of the interaction between LULC, climate (specifically variable hydrologic forcing) and solute export across seasonal and interannual time scales is needed to understand the processes that determine nutrient loading and responses to change. Recent advances in high-frequency water quality sensors provide opportunities to assess these interannual relationships with sufficiently high temporal resolution to capture the unpredictable, short-term storm events that likely drive important export mechanisms for dissolved organic carbon (DOC) and nitrate (NO 3 − –N). We deployed a network of in situ sensors in forested, agricultural, and urban watersheds across the northeastern United States. Using 2 years of high-frequency sensor data, we provide a regional assessment of how LULC and hydrologic variability affected the timing and magnitude of dissolved organic carbon and nitrate export, and the status of watershed fluxes as either supply or transport controlled. Analysis of annual export dynamics revealed systematic differences in the timing and magnitude of DOC and NO 3 − –N delivery among different LULC classes, with distinct regional similarities in the timing of DOC and NO 3 − –N fluxes from forested and urban watersheds. Conversely, export dynamics at agricultural sites appeared to be highly site-specific, likely driven by local agricultural practices and regulations. Furthermore, the magnitude of solute fluxes across watersheds responded strongly to interannual variability in rainfall, suggesting a high degree of hydrologic control over nutrient loading across the region. Thus, there is strong potential for climate-driven changes in regional hydrologic cycles to drive variation in the magnitude of downstream nutrient fluxes, particularly in watersheds where solute supply and/or transport has been modified.

Delaware, Rhode Island, Vermont↗

USGS2018

Using in situ UV-Visible spectrophotometer sensors to quantify riverine phosphorus partitioning and concentration at a high frequency

Accurate riverine phosphorus concentration measurements are often critical to meet watershed management goals. Phosphorus monitoring programs often rely on proxy variables such as turbidity and discharge and have limited ability to accurately estimate concentrations of dissolved phosphorus fractions that are most bioavailable. Optical water quality sensors can make subhourly measurements and have been shown to reduce uncertainty in load estimates and reveal high-frequency storm dynamics for nitrate and dissolved organic carbon. We evaluated the utility of in situ UV-Visible spectrophotometers to predict total, dissolved, and soluble reactive phosphorus concentrations in streams draining agricultural, urban, and forested land use/land covers. We present the first statistically validated application of optical water quality sensors to demonstrate how sensors may perform in predicting phosphorus fraction concentrations through training set models. Total phosphorus predictions from UV-Visible spectra were optimal when models were site-specific, and the proportion of variance explained was generally as high as or higher than the results of other studies that rely only on discharge and turbidity. However, root mean square errors for total phosphorus models were relatively high compared to the median concentrations at each site. Models to predict dissolved and soluble reactive phosphorus concentrations explained a greater proportion of the variance than any other known proxy variable technique, and results varied by land use/land cover. Though accuracy limitations remain, this approach has potential to predict concurrent total, dissolved, and soluble reactive phosphorus concentrations at a high frequency for many applications in water quality research and management communities.

Vermont↗