Crowdsourcing The National Map

Using crowdsourcing techniques, the US Geological Survey’s (USGS) Volunteered Geographic Information (VGI) project known as “The National Map Corps (TNMCorps)” encourages citizen scientists to collect and edit data about man-made structures in an effort to provide accurate and authoritative map data for the USGS National Geospatial Program’s web-based The National Map. VGI is not new to the USGS, but past efforts have been hampered by available technologies. Building on lessons learned, TNMCorps volunteers are successfully editing 10 different structure types in all 50 states as well as Puerto Rico and the US Virgin Islands.     

Fifty-eight years and counting of watershed science at the Caspar Creek Experimental Watersheds in northern California

The Caspar Creek Experimental Watersheds are the site of a long-term paired watershed study in the northern Coast Ranges of California. The watersheds are predominately forested with coast redwood and Douglas-fir. Old-growth forest was logged between 1860 and 1904. Two harvesting experiments have been completed since then and a third experiment is currently underway. Caspar Creek data are split into three phases corresponding to three experiments: Phase 1 (1962–1985) reports on a selection harvest (1971–1973) and initial recovery in the South Fork watershed; Phase 2 (1985–2017) includes clearcut harvesting of ~50% of the North Fork watershed (1985–1992) and recovery; and Phase 3 (2017 onward) corresponds to a second selection harvest in the South Fork watershed with a range of subwatershed harvest intensities (2017–2019) and recovery. All three experiments included harvest-related road-building and relied primarily on measurements of streamflow and sediment delivery from both treated and reference watersheds. Major findings include modest increases in post-harvest peak flows and cumulative flow volumes, post-harvest low flows that initially increased and then decreased 12 to 15 years after harvesting, and the consequences of different yarding techniques and road design on sediment yields. Some of the data for Phase 1 and Phase 2 are available in a USDA Forest Service online archive. The archived data include precipitation, streamflow, suspended sediment concentrations, turbidity, accumulated weir pond sediment volumes, bedload transport rates, water stable isotope data, and geospatial data. Archiving activities are ongoing. Phase 3 data are currently being collected and will be archived after a post-harvest monitoring period.     

CHOSEN: A synthesis of hydrometeorological data from intensively monitored catchments and comparative analysis of hydrologic extremes

Comparative hydrology has been hampered by limited availability of geographically extensive, intercompatible monitoring data on comprehensive water balance stores and fluxes. These limitations have, for example, restricted comprehensive assessment of multiple dimensions of wetting and drying related to climate change and hampered understanding of why widespread changes in precipitation extremes are uncorrelated with changes in streamflow extremes. Here, we address this knowledge gap and underlying data gap by developing a new data synthesis product and using that product to detect trends in the frequencies and magnitudes of a comprehensive set of hydroclimatic and hydrologic extremes. CHOSEN (Comprehensive Hydrologic Observatory Sensor Network) is a database of streamflow, soil moisture, and other hydroclimatic and hydrologic variables from 30 study areas across the United States. An accompanying data pipeline provides a reproducible, semi-automated approach for assimilating data from multiple sources, performing quality assurance and control, gap-filling and writing to a standard format. Based on the analysis of extreme events in the CHOSEN dataset, we detected hotspots, characterized by unusually large proportions of monitored variables exhibiting trends, in the Pacific Northwest, New England, Florida and Alaska. Extreme streamflow wetting and drying trends exhibited regional coherence. Drying trends in the Pacific Northwest and Southeast were often associated with trends in soil moisture and precipitation (Pacific Northwest) and evapotranspiration-related variables (Southeast). In contrast, wetting trends in the upper Midwest and the Rocky Mountains showed few univariate associations with other hydroclimatic extremes, but their latitudes and elevations suggested the importance of changing snowmelt characteristics. On the whole, observed trends are incompatible with a ‘drying-in-dry, wetting-in-wet’ paradigm for climate-induced hydrologic changes over land. Our analysis underscores the need for more extensive, longer-term observational data for soil moisture, snow and evapotranspiration.     

Estuarine phytoplankton group-specific responses to sublethal concentrations of the agricultural herbicide,atrazine

Atrazine is a common agricultural herbicide that is readily transported into estuaries through surface water runoff. In this study, we determined the short-term (24-48 h) sublethal effects of atrazine on estuarine phytoplankton biomass and community composition. Phytoplankton group-specific responses to atrazine exposure (25 microgh(-1)) were measured using natural water samples collected from two locations in Galveston Bay, Texas. Addition bioassays, coupled with HPLC pigment analysis, were used to quantify changes in the relative abundances of algal groups. For all algal groups except prasinophytes, the addition of atrazine in combination with nitrate was not significantly different from nitrate additions alone. These results suggest no significant negative effect of atrazine on phytoplankton under the specified environmental conditions for the bioassays. Although low concentrations of atrazine may have minimal impacts on phytoplankton, herbicide loadings need to be further characterized before generalizations can be applied to estuarine and coastal ecosystems.     

Optimization strategies for sediment reduction practices on roads in steep,forested terrain

Many forested steeplands in the western United States display a legacy of disturbances due to timber harvest, mining or wildfires, for example. Such disturbances have caused accelerated hillslope erosion, leading to increased sedimentation in fish‐bearing streams. Several restoration techniques have been implemented to address these problems in mountain catchments, many of which involve the removal of abandoned roads and re‐establishing drainage networks across road prisms. With limited restoration funds to be applied across large catchments, land managers are faced with deciding which areas and problems should be treated first, and by which technique, in order to design the most effective and cost‐effective sediment reduction strategy. Currently most restoration is conducted on a site‐specific scale according to uniform treatment policies. To create catchment‐scale policies for restoration, we developed two optimization models – dynamic programming and genetic algorithms – to determine the most cost‐effective treatment level for roads and stream crossings in a pilot study basin with approximately 700 road segments and crossings. These models considered the trade‐offs between the cost and effectiveness of different restoration strategies to minimize the predicted erosion from all forest roads within a catchment, while meeting a specified budget constraint. The optimal sediment reduction strategies developed by these models performed much better than two strategies of uniform erosion control which are commonly applied to road erosion problems by land managers, with sediment savings increased by an additional 48 to 80 per cent. These optimization models can be used to formulate the most cost‐effective restoration policy for sediment reduction on a catchment scale. Thus, cost savings can be applied to further restoration work within the catchment. Nevertheless, the models are based on erosion rates measured on past restoration sites, and need to be updated as additional monitoring studies evaluate long‐term basin response to erosion control treatments. Copyright © 2006 John Wiley & Sons, Ltd.     

E‐tracers: Development of a low cost wireless technique for exploring sub‐surface hydrological systems

This briefing describes the first deployment of a new electronic tracer (E‐tracer) for obtaining along‐flowpath measurements in subsurface hydrological systems. These low‐cost, wireless sensor platforms were deployed into moulins on the Greenland Ice Sheet. After descending into the moulin, the tracers travelled through the subglacial drainage system before emerging at the glacier portal. They are capable of collecting along‐flowpath data from the point of injection until detection. The E‐tracers emit a radio frequency signal, which enables sensor identification, location and recovery from the proglacial plain. The second generation of prototype E‐tracers recorded water pressure, but the robust sensor design provides a versatile platform for measuring a range of parameters, including temperature and electrical conductivity, in hydrological environments that are challenging to monitor using tethered sensors. Copyright © 2012 John Wiley & Sons, Ltd.     

Consequences of actor level livelihood heterogeneity for additionality in a tropical forest payment for environmental services programme with an undifferentiated reward structure

Primary tropical forests provide crucial environmental services, including carbon storage and hydrological regulation. Options for promoting forest conservation include payments for environmental services (PES) programmes that provide financial incentives to local actors, in exchange for reduced forest clearance. The success of voluntary PES (defined in terms of avoided primary forest conversion) is contingent upon behavioural changes in enrolled actors. As both the degree of enrolment and likelihood of sustained behavioural change depend upon how PES compensation structures interact with existing actor economies, local heterogeneity in livelihood strategies may play a strong role in the ultimate success of PES programmes, particularly when compensation is not differentiated with respect to opportunity costs. We examined the influence of livelihood heterogeneity on the potential success of a deforestation-reduction PES with an undifferentiated reward structure. We collected socioeconomic and demographic data at the household and community levels across two large Amazonian extractive reserves where a spatially extensive PES programme (Bolsa Floresta) operates. We show that demographic and socioeconomic status varies widely across households and communities, and found that both households and communities that are most and least likely to convert primary forest receive similar financial incentives. Those households most engaged in manioc agriculture (the primary driver of local primary forest conversion) both benefitted from the highest annual incomes and incurred the greatest opportunity costs. We show that avoided primary forest conversion could be greatly increased with differentiated payment structures adjusted for local differences in opportunity costs and livelihood strategies, and present two metrics that could help to achieve that goal.     

Coupling basin- and site-scale inverse models of the Española aquifer

Large-scale models are frequently used to estimate fluxes to small-scale models. The uncertainty associated with these flux estimates, however, is rarely addressed. We present a case study from the Espa?ola Basin, northern New Mexico, where we use a basin-scale model coupled with a high-resolution, nested site-scale model. Both models are three-dimensional and are analyzed by codes FEHM and PEST. Using constrained nonlinear optimization, we examine the effect of parameter uncertainty in the basin-scale model on the nonlinear confidence limits of predicted fluxes to the site-scale model. We find that some of the fluxes are very well constrained, while for others there is fairly large uncertainty. Site-scale transport simulation results, however, are relatively insensitive to the estimated uncertainty in the fluxes. We also compare parameter estimates obtained by the basin- and site-scale inverse models. Differences in the model grid resolution (scale of parameter estimation) result in differing delineation of hydrostratigraphic units, so the two models produce different estimates for some units. The effect is similar to the observed scale effect in medium properties owing to differences in tested volume. More important, estimation uncertainty of model parameters is quite different at the two scales. Overall, the basin inverse model resulted in significantly lower estimates of uncertainty, because of the larger calibration dataset available. This suggests that the basin-scale model contributes not only important boundary condition information but also improved parameter identification for some units. Our results demonstrate that caution is warranted when applying parameter estimates inferred from a large-scale model to small-scale simulations, and vice versa.