Thomas Brook Research Articles

Trichomycete prevalence in Thomas Brook, Nova Scotia, exposed to different levels of human activity

The Thomas Brook in the Annapolis Valley, Nova Scotia, was the focus of an Agriculture and Agri-Food Canada wastershed evaluation of beneficial management practices (WEBs) project from 2004–2008. The stream is impacted by human activities along its course, with residential influences and farming operations. The water quality in Thomas Brook was assessed in 2006, and the current study done in 2011–2012 used the same standard invertebrate metrics to measure water quality. This project also examined the prevalence of gut endosymbionts (trichomycetes) in aquatic invertebrates to determine whether water quality affects this community of obligate microorganisms in their hosts. The water quality was improved in Thomas Brook in 2011/2012 compared with that measured in the earlier study. There were 34 taxa of trichomycetes recorded in benthic insects in the stream, including two new species. The trichomycete community was rich in dipteran hosts (midges and black fly larvae), but the prevalence of gut fungi in ephemeropteran (mayfly) nymphs in the system was low, perhaps due to the impact of human activities on water quality.

Catchment-Scale Integrated Surface Water-Groundwater Hydrologic Modelling Using Conceptual and Physically Based Models: A Model Comparison Study

This paper presents a comparative analysis of the use of an externally linked (MOBIDIC-MODFLOW) and a physically based (MIKE SHE) surface water-groundwater model to capture the integrated hydrologic responses of the Thomas Brook catchment, in Canada. The main objective of the study is to investigate the effect of simplification in representation of the hydrological processes in MOBIDIC-MODFLOW on its simulation accuracy. To this aim, MOBIDIC and MODFLOW were coupled in order to sequentially exchange the groundwater recharge and baseflow discharges within each computation time step. Using identical sets of hydrogeological properties for the two models, the coefficients of the gravity and capillary reservoirs in MOBIDIC were calibrated so as to closely predict the hydrological budget of the catchment simulated with MIKE SHE. The simulated results show that the two models can closely replicate the observed water table responses at two monitoring wells. However, in very shallow water table locations, the instantaneous response of the water table was not precisely captured in MOBIDIC-MODFLOW. Additionally, the simplified conceptualization of the unsaturated flow in MOBIDIC-MODFLOW resulted in overestimated groundwater recharge during spring and underestimation during summer. Moreover, the computational efficiency of MOBIDIC-MODFLOW, as compared to MIKE SHE, along with less required input data, confirms its potential for regional scale groundwater-surface water interaction modelling applications.

Climate Change Predictions of Increased Watershed Flow in Atlantic Canada: Implications for Surface Water Vulnerability and Ameliorative Land Use Planning and Management

Essential for comprehensive and sustainable watershed management is the need to understand interactions between climate change predictions and landuse modifications in concert on ecohydrology. The Atlantic Canada region is expected to experience elevated rainfall due to climate change over the next century. We undertook a predictive modeling study of a watershed in rural Nova Scotia, Thomas Brook, to investigate the potential of riparian reforestation to mitigate the deleterious environmental effects projected to occur from future climate change. A Watershed Analysis Risk Management Framework (WARMF) model was used to predict increased watershed flows using data from projections of the Canadian Regional Climate Change Model. The cold climate-validated WARMF model, which has been used previously to simulate surface flow hydrology in many agricultural and mixed-use landscapes, was found to predict increases of 9% to 25% in flow for the Thomas Brook watershed throughout the rest of the century. A spatial, exposure-based model, used previously in several studies, was adopted for assessing changes in surface water vulnerability based on GIS land-use and landscape topography estimates of nutrient loading, sedimentation, runoff, wetland loss, and stream geomorphology. This model indicated that increases in drainage intensity and drainage sensitivity expected through the climate change WARMF model resulted in greater proportions (from 5% to 27%) of the Thomas Brook watershed area being classified as “High vulnerability” for impacting surface water quality. In terms of land use planning, implementation of runoff and nutrient entrapment techniques through low impact development may need to become increasingly required in order to maintain aquatic health. In terms of land-use management, empirically increasing the width of riparian forest buffers was projected to reduce the predicted areal extent of “High vulnerability”. However, widths of 90 m would be required in order to achieve the same degree of protection that presently exists. Our conclusions are that climate-proofing this watershed through riparian reforestation would come at a cost in terms of the extent of land needed to be set aside by being taken out of agricultural production or commercial forestry.

Spatially-Explicit, Exposure-Based Assessment of Surface Water Vulnerability from Land Use Threats for Time-Efficient and Cost-Effective Watershed Development Planning

The utility of a spatially-explicit, exposure-based model was examined for its suitability as a tool for rapidly assessing surface water vulnerability in watershed planning. This simple GIS-model uses three types of easily obtainable spatial information: (1) sources of land use-induced change; (2) intensity of watershed drainage; and (3) sensitivity of drainage basins to change. This model was applied to the Thomas Brook watershed in Nova Scotia, Canada, which has been the site of previous studies, conducted over multiple years, using detailed, effects-based, hydrologic models. Doing so allowed us the opportunity to compare the two approaches. Results showed a good concordance in the derived mapped outputs between the two models. Given the rapid ease and inexpensive cost of using the GIS, exposure-based model, we believe it to offer great promise in terms of prioritizing locations for further study or for intervention of best management practices, as well as for planning where to best direct future water-sensitive development through build-out analyses.

Adventures of Huckleberry Finn and Reconstruction

Research Article| October 01 2017 Adventures of Huckleberry Finn and Reconstruction Brook Thomas Brook Thomas University of California, Irvine Search for other works by this author on: This Site Google American Literary Realism (2017) 50 (1): 1–24. https://doi.org/10.5406/amerlitereal.50.1.0001 Cite Icon Cite Share Icon Share Facebook Twitter LinkedIn MailTo Permissions Search Site Citation Brook Thomas; Adventures of Huckleberry Finn and Reconstruction. American Literary Realism 1 January 2017; 50 (1): 1–24. doi: https://doi.org/10.5406/amerlitereal.50.1.0001 Download citation file: Zotero Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All Scholarly Publishing CollectiveUniversity of Illinois PressAmerican Literary Realism Search Advanced Search The text of this article is only available as a PDF. Copyright 2017 by the Board of Trustees of the University of Illinois2017 Article PDF first page preview Close Modal Issue Section: Essays You do not currently have access to this content.

Modeling Impacts of Residential and Agricultural Development and Beneficial Management Practice Scenarios on Phosphorus Dynamics in a Small Watershed

<abstract> <b><sc>Abstract.</sc></b> Both agricultural land uses and residential on-site wastewater systems (OWS) have the potential to be nonpoint sources of phosphorus (P) in rural watersheds. Watershed-scale computer models are a commonly used tool for evaluating the impacts of increased human development on P dynamics and for evaluating how beneficial management practices (BMPs) can reduce P loading. Many agricultural field BMPs have been evaluated using watershed-scale models; however, no studies have compared their efficacy to OWS BMPs in a mixed land use watershed. The objectives of this research were to (1) use the P on-site wastewater simulator (POWSIM) and the Soil and Water Assessment Tool (SWAT) to simulate different agricultural and residential development scenarios in the Thomas Brook watershed in Nova Scotia, Canada, and evaluate their impacts on sediment and total P (TP) loads and TP concentrations and (2) simulate and evaluate different individual and combinations of select agricultural and OWS BMPs. A 50-year simulation period was used for both the development and BMP scenarios. The development scenarios evaluated included increasing the residential population and conversion of hay fields or pastures to corn-based cropping regimes. The agricultural BMPs evaluated were (1) corn and rotational crop replacement with no-till agricultural land uses and (2) no-till corn. Decreased failure rates, increased watercourse setbacks, disposal field replacement, and the use of high P sorption filter media were the OWS BMPs evaluated. The agricultural development scenarios increased cumulative sediment and P loads at the watershed outlet, while the residential scenarios increased the frequency of hyper-eutrophic conditions in the stream during the last 20 simulated years. Agricultural crop replacement BMPs produced the highest reductions in cumulative sediment (13% to 46%) and TP loads (26% to 34%) but had no observable change on the in-stream trophic status. The OWS BMPs produced small reductions in TP loading (2% to 15%), no sediment load reductions, but had a positive effect on the trophic status. The best ranked combination of agricultural and OWS BMPs resulted in a cumulative TP load reduction of 58%, and the dominant trophic state at the end of the 50-year period was mesotrophic, as compared to eutrophic for the reference simulation. The best combination BMP scenario included replacing corn and rotational crops with pastures, using high P sorption filter media (5000 mg P kg^-1 media), and lowering of the OWS failure rate to 5%. The results of these modeling scenarios showed that agricultural BMPs were most effective in reducing cumulative P loads, while OWS BMPs were effective in mitigating in-stream eutrophication impacts. This study highlights the importance of identifying specific water quality issues that need to be targeted prior to implementing a watershed BMP strategy. Further model refinement and testing are required with improved field measurements to improve model confidence before the model should be used for planning and design purposes.

Sensitivity of Hydrological Outputs from SWAT to DEM Spatial Resolution

This research analyzes the sensitivity of the SWAT (Soil and Water Assessment Tool) flow rate and sediment yield to DEM spatial resolution. A scaling analysis is performed using 1 to 50 m resolution lidar (Light Detection and Ranging) derived DEMs. Thomas Brook, Canada, serves as a case study watershed for a five year simulation period. Results indicated monthly water yield was insensitive to DEM resolution, unless a change in area was also present. Sediment yield from the 50 m DEM showed a 200 t reduction compared to the 1 m DEM. The 5 to 50 m DEMs also showed a reduction in channel deposition of 45 to 90 t, respectively, compared to the 1 m DEM. Results suggest parameterization using multiple resolution DEMs is desirable, one commensurate with the scale used to establish universal soil loss equations for defining hillslope scale, and high resolution for stream network and sub-basin delineation.

A Watershed Modeling Framework for Phosphorus Loading from Residential and Agricultural Sources

Phosphorus (P) loading from residential onsite wastewater systems (OWSs) into neighboring surface waters is a poorly understood process in rural watersheds; this can be further challenged when rural residential dwellings are intermixed with agricultural land use. The objectives of this research were (i) to design a P onsite wastewater simulator (POWSIM) to assess P loads from individual or clusters of residential OWSs typically used in Nova Scotia, Canada; and (ii) to simulate OWS P loads in a mixed agricultural watershed (Thomas Brook Watershed [TBW], NS) using the Soil and Water Assessment Tool (SWAT) model in conjunction with POWSIM, to predict and compare P loading from agricultural and residential sources. The POWSIM loading tool has three computational components: (i) disposal field selection and treatment media mass calculation, (ii) disposal field P treatment dynamics, and (iii) soil subsurface plume P treatment dynamics. The combination TBW POWSIM and SWAT modeling approach produced a better simulation of baseflow total P (TP) loads in both a predominantly residential subcatchment and one dominated by agriculture than the SWAT model without POWSIM. The residential subcatchment had 48% of its average annual land use TP load (simulated) contributed by OWSs, whereas the agricultural subcatchment had 39%. Watershed-scale sensitivity analyses of POWSIM input parameters for 18- and 50-yr OWS operation periods found the P loading rate into the disposal field, long-term P removal rates in the disposal field and soil systems, soil maximum P sorption capacity, and mass of native soil involved in P treatment to be most sensitive.

Sensitivity of watershed attributes to spatial resolution and interpolation method of LiDAR DEMs in three distinct landscapes

AbstractThis study investigates scaling relationships of watershed area and stream networks delineated from LiDAR DEMs. The delineations are tested against spatial resolution, including 1, 5, 10, 25, and 50 m, and interpolation method, including Inverse Distance Weighting (IDW), Moving Average (MA), Universal Kriging (UK), Natural Neighbor (NN), and Triangular Irregular Networks (TIN). Study sites include Mosquito Creek, Scotty Creek, and Thomas Brook, representing landscapes with high, low, and moderate change in elevation, respectively. Results show scale‐dependent irregularities in watershed area due to spatial resolution at Thomas Brook and Mosquito Creek. The highest sensitivity of watershed area to spatial resolution occurred at Scotty Creek, due to high incidence of LiDAR sensor measurement error and subtle changes in elevation. Length of drainage networks did not show a scaling relationship with spatial resolution, due to algorithmic complications of the stream initiation threshold. Stream lengths of main channels at Thomas Brook and Mosquito Creek displayed systematic increases in length with increasing spatial resolution, described through an average fractal dimension of 1.059. The scaling relationship between stream length and DEM resolution allows estimation of stream lengths from low‐resolution DEMs in the absence of high‐resolution DEMs. Single stream validation at Thomas Brook showed the 1 m DEM produced the lowest length error and highest spatial accuracy, at 3.7% and 71.3%, respectively. Single stream validation at Mosquito Creek showed the 25 m DEM produced the lowest length error, and the 1 m DEM the highest spatial accuracy, at 0.6% and 61.0%, respectively.

Effect of Nutrient Management Planning on Crop Yield, Nitrate Leaching and Sediment Loading in Thomas Brook Watershed

Government priorities on provincial Nutrient Management Planning (NMP) programs include improving the program effectiveness for environmental quality protection, and promoting more widespread adoption. Understanding the effect of NMP on both crop yield and key water-quality parameters in agricultural watersheds requires a comprehensive evaluation that takes into consideration important NMP attributes and location-specific farming conditions. This study applied the Soil and Water Assessment Tool (SWAT) to investigate the effects of crop and rotation sequence, tillage type, and nutrient N application rate on crop yield and the associated groundwater [Formula: see text] leaching and sediment loss. The SWAT model was applied to the Thomas Brook Watershed, located in the most intensively managed agricultural region of Nova Scotia, Canada. Cropping systems evaluated included seven fertilizer application rates and two tillage systems (i.e., conventional tillage and no-till). The analysis reflected cropping systems commonly managed by farmers in the Annapolis Valley region, including grain corn-based and potato-based cropping systems, and a vegetable-horticulture system. ANOVA models were developed and used to assess the effects of crop management choices on crop yield and two water-quality parameters (i.e., [Formula: see text] leaching and sediment loading). Results suggest that existing recommended N-fertilizer rate can be reduced by 10-25%, for grain crop production, to significantly lower [Formula: see text] leaching (P>0.05) while optimizing the crop yield. The analysis identified the nutrient N rates in combination with specific crops and rotation systems that can be used to manage [Formula: see text] leaching while balancing impacts on crop yields within the watershed.

Modeling Sediment and Nitrogen Export from a Rural Watershed in Eastern Canada Using the Soil and Water Assessment Tool

Watershed simulation models can be used to assess agricultural nonpoint-source pollution and for environmental planning and improvement projects. However, before application of any process-based watershed model, the model performance and reliability must be tested with measured data. The Soil and Water Assessment Tool version 2005 (SWAT2005) was used to model sediment and nitrogen loads from the Thomas Brook Watershed, which drains a 7.84 km rural landscape in the Annapolis Valley of Nova Scotia, Canada. The Thomas Brook SWAT model was comprised of 28 subbasins and 265 hydrologic response units, most of them containing agricultural land use, which is the main nonpoint nitrogen source in the watershed. Crop rotation schedules were incorporated into the model using field data collected within Agriculture and Agri-Food Canada's Watershed Evaluation of Beneficial Management Practices program. Model calibration (2004-2006) and validation (2007-2008) were performed on a monthly basis using continuous stream flow, sediment, and nitrogen export measurements. Model performance was evaluated using the coefficient of determination, Nash-Sutcliff efficiency (NSE), and percent bias (PBIAS) statistics. Study results show that the model performance was satisfactory (NSE > 0.4; > 0.5) for stream flow, sediment, nitrate-nitrogen, and total nitrogen simulations. Annual corn, barley, and wheat yields were also simulated well, with PBIAS values ranging from 0.3 to 7.2%. This evaluation of SWAT demonstrated that the model has the potential to be used as a decision support tool for agricultural watershed management in Nova Scotia.

Reconstructing State and Federal Jurisdiction in A Fool's Errand and The Clansman

Research Article| September 01 2010 Reconstructing State and Federal Jurisdiction in A Fool's Errand and The Clansman Brook Thomas Brook Thomas University of California, Irvine bthomas@uci.edu Brook Thomas is Chancellor's Professor of English at the University of California, Irvine. His books on law and literature include Civic Myths: A Law and Literature Approach to Citizenship (University of North Carolina Press, 2007); American Literary Realism and the Failed Promise of Contract (University of California Press, 1997); Cross-Examinations of Law and Literature: Cooper, Hawthorne, Stowe, and Melville (Cambridge University Press, 1987); and “Plessy v. Ferguson”: A Brief History with Documents (Bedford/St. Martin's, 1996). He has also written numerous essays on the topic, including “A Constitution Led by the Flag: The Insular Cases and the Metaphor of Incorporation,” “Stigmas, Badges, and Brands: Discriminating Marks in Legal History,” “Plessy v. Ferguson and the Literary Imagination,” “Reflections on the Law and Literature Revival,” and “Stanley Fish and the Uses of Baseball: The Return of the Natural”. Search for other works by this author on: This Site Google English Language Notes (2010) 48 (2): 71–83. https://doi.org/10.1215/00138282-48.2.71 Cite Icon Cite Share Icon Share Facebook Twitter LinkedIn MailTo Permissions Search Site Citation Brook Thomas; Reconstructing State and Federal Jurisdiction in A Fool's Errand and The Clansman. English Language Notes 1 September 2010; 48 (2): 71–83. doi: https://doi.org/10.1215/00138282-48.2.71 Download citation file: Zotero Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search Books & JournalsAll JournalsEnglish Language Notes Search Advanced Search The text of this article is only available as a PDF. Copyright © 2010 Regents of the University of Colorado2010 Article PDF first page preview Close Modal You do not currently have access to this content.

A modeling study of heterogeneity and surface water-groundwater interactions in the Thomas Brook catchment, Annapolis Valley (Nova Scotia, Canada)

Abstract. A modelling study of the impacts of subsurface heterogeneity on the hydrologic response of a small catchment is reported. The study is focused in particular on the hydraulic connection and interactions between surface water and groundwater. A coupled (1-D surface/3-D subsurface) numerical model is used to investigate, for a range of scenarios, the spatio-temporal patterns of response variables such as return flow, recharge, groundwater levels, surface saturation, and streamflow. Eight scenarios of increasing geological complexity are simulated for an 8 km2 catchment in the Annapolis Valley (eastern Canada), introducing at each step more realistic representations of the geological strata and corresponding hydraulic properties. In a ninth scenario the effects of snow accumulation and snowmelt are also considered. The results show that response variables and significant features of the catchment (e.g. springs) can be adequately reproduced using a representation of the geology and model parameter values that are based on targeted fieldwork and existing databases, and that reflect to a sufficient degree the geological and hydrological complexity of the study area. The hydraulic conductivity values of the thin surficial sediment cover (especially till) and of the basalts in the upstream reaches emerge as key elements of the basin's heterogeneity for properly capturing the overall catchment response.

Growing season surface water loading of fecal indicator organisms within a rural watershed

The loading of microbial contaminants was examined within the Thomas Brook watershed, a 784 ha mixed land-use catchment located in the headwaters of the Cornwallis River drainage basin (Nova Scotia, Canada). The objectives were to: (i) examine spatial and temporal characteristics of fecal bacteria loading during the growing season from five subwatersheds, and (ii) develop areal fecal indicator organism export coefficients for rural landscapes. Fecal coliform, Escherichia coli, total suspended solids (TSS) concentrations and stream flow were monitored at five locations in the watershed over six consecutive growing seasons (May–Oct, 2001–2006). A nested watershed monitoring approach was used to determine bacterial loading from distinct source types (residential vs. agricultural) during both baseflow and stormflow periods. Areal bacterial loading rates increased in each nested watershed moving downstream through the watershed and were highest in the three subcatchments dominated by agricultural activities. Upper watershed bacterial loading throughout the growing season from an agricultural subcatchment (Growing Season Avg 8.92 × 10 10 CFU ha −1) was consistently higher than a residential subcatchment (Growing Season Avg 8.43 × 10 9 CFU ha −1). As expected, annual average stormflow bacterial loads were higher than baseflow loads, however baseflow loads still comprised between 14 and 35% of the growing season bacterial loads in the five subwatersheds. Fecal bacteria loads were greater during years with higher annual precipitation. A positive linear relationship was observed between E. coli and TSS loading during the 2005 and 2006 growing seasons when both parameters were monitored, indicating that the processes of sediment transport and bacterial transport are linked. It is anticipated that computed areal microbial loading coefficients will be useful in developing watershed management plans. More intensive sampling during stormflow events is recommended for improving these coefficients.

Stream ecosystem health in rural mixed land-use watersheds

A paired stream approach was used to assess ecosystem health in two rural Nova Scotia streams (Thomas Brook and Sharpe Brook) with varying land-use practices. The objectives of the study were to assess stream health within an agricultural catchment, the Thomas Brook Watershed, and to identify parameters that could be used to characterize the impacts of agricultural land use on stream ecosystem health within intensively farmed watersheds in Nova Scotia. General water quality (nutrient concentrations, turbidity, pH, temperature) and the hydrology of both watersheds were monitored from May to October 2006. In addition, continuous dissolved oxygen (DO) and chlorophyll a data were collected in both streams, and benthic invertebrate populations were characterized during the study period. Diurnal DO data were analyzed to determine photosynthesis and respiration ratios. Macroinvertebrate data provided information on productivity, and on a number of other relevant metrics. Findings determined that agricultural land-use generally led to high nutrient concentrations, large dissolved oxygen variability, turbid waters, high chlorophyll a content, and impacted macroinvertebrate populations in streams. Forested land-use demonstrated typically unimpacted conditions. It was concluded that DO dynamics and macroinvertebrate metrics would be very useful for providing a generalized assessment of stream health in agricultural watersheds.

Sources and Persistence of Fecal Coliform Bacteria in a Rural Watershed

Abstract Water quality within the Thomas Brook watershed, which is a small catchment located in the headwaters of the Cornwallis River drainage basin, was assessed through an integrated monitoring program. The Thomas Brook watershed is approximately 1000 ha and is characterized by both agricultural and residential land uses. Fecal coliform concentrations and stream flow were monitored at several points throughout the watershed during an eight-month period (May to December, 2001). Thomas Brook was seriously degraded with respect to microbial water quality. Fecal coliform levels frequently exceeded recreational water quality guidelines. At the watershed outlet, 94% of the collected samples exceeded the recreational water quality guideline during low flow conditions. Substantial bacterial loading was observed along stream reaches impacted by livestock operations. Bacterial loading was also observed along a stream reach that was not impacted by agricultural activities. A dense clustering of residences, using on-site septic systems, was the suspected source. Results from this study indicate the presence of a reservoir of fecal microorganisms within the stream sediments. The release of fecal microorganisms from the stream sediments to the water column during both low and high flow conditions could be a major source of bacterial loading.

Citizen Hester: The Scarlet Letter as Civic Myth

Journal Article Citizen Hester: The Scarlet Letter as Civic Myth Get access Brook Thomas Brook Thomas Search for other works by this author on: Oxford Academic Google Scholar American Literary History, Volume 13, Issue 2, Summer 2001, Pages 181–211, https://doi.org/10.1093/alh/13.2.181 Published: 01 July 2001

American Literary Realism and the Failed Promise of Contract

Journal Article American Literary Realism and the Failed Promise of Contract Get access Thomas Brook, American Literary Realism and the Failed Promise of Contract. Berkeley and Los Angeles: University of California Press, 1997. xiii, 359 pp. $35.00. Maxwell Bloomfield Maxwell Bloomfield The Catholic University of America Search for other works by this author on: Oxford Academic Google Scholar American Journal of Legal History, Volume 42, Issue 1, January 1998, Pages 98–100, https://doi.org/10.2307/846027 Published: 01 January 1998

Tragedies of Race, Training, Birth, and Communities of Competent Pudd'nheads

Tragedies of Race, Training, Birth, and Communities of Competent Pudd'nheads Get access Brook Thomas Brook Thomas Search for other works by this author on: Oxford Academic Google Scholar American Literary History, Volume 1, Issue 4, Winter 1989, Pages 754–785, https://doi.org/10.1093/alh/1.4.754 Published: 01 December 1989