Water resources management

Eutrophication is an ongoing global problem and agriculture is an important non-point source of nutrient loading. Specifically, nitrogen (N) and phosphorus (P) losses from agricultural landscapes continue to drive water quality issues. In southern Ontario, agriculture has intensified in recent decades, with major expansions of cash crop production and extensive tile drainage (TD). Through intensive monitoring of 12 tile outlets draining operational fields under the conventional corn-soybean-wheat rotation, this study examined differences in measured and volume-weighted total P, total N, and nitrate-N concentrations and loads over 28 months (October 2020- April 2023) amongst crop covers and between growing (GS; May – September) and non-growing seasons (NGS; October – April). Nitrogen concentrations (i.e., TN and NO3-N) in TD eluent were consistently high both between seasons and were found to be significantly highest from winter wheat (WW) fields in the NGS, and corn fields in the GS. Volume-weighted TP concentrations were not significantly different either amongst crop covers or between seasons, although TP losses tended to be highest from the cover crop (CC) fields in the NGS. Differences in N and P losses between years and amongst crop covers were attributed to differences in legacy soil nutrients, the establishment and decomposition of over-winter cover crops, and physical soil properties. The results of this study can inform agricultural management by addressing the urgent need for improved information around the relationship between agricultural practices and nutrient losses, especially in the NGS.

Author Keywords: Best management practices, Crop rotation, Over-winter cover crops, Seasonality, Tile drainage, Water quality

Although stormwater management ponds (SWMPs) are frequently used to mitigate flooding in urban areas, we still do not fully understand how these systems impact water quality in a watershed. Currently, most research focuses on the effectiveness of SWMPs to retain nutrients during high flows, even though there is potential for internal nutrient releases to occur in these systems during low flows. To investigate if SWMPs act as nutrient sources or sinks during low flow conditions, we analyzed how sewershed characteristics, pond properties, and hydrological and limnological factors influenced nutrient dynamics and stoichiometry in 10 SWMPs. Our study ponds were located in Peterborough, Whitby, and Richmond Hill, which are urbanized municipalities in southern Ontario, Canada. During October 2010 to 2011, we took monthly measurements of various carbon (C), nitrogen (N), and phosphorus (P) forms. We collected samples in the inlets, permanent pools, and outlets to determine any changes in concentrations, loads, and stoichiometric ratios into and out of the ponds. At the time of sampling, we also measured a variety of hydrological and limnological parameters. Our findings indicate that more urbanized sewersheds with higher drainage densities tend to have higher inflowing particulate and dissolved nutrient loads. In addition, we found that pond properties such as depth, length-to-width ratio, volume, and age differentially influence the retention of particulate and dissolved C, N, and P forms. Influential hydrological and limnological factors were antecedent moisture conditions, season, and thermal stratification. We found higher particulate P concentrations near the sediments when the catchments were drier and the ponds were ice-free and stratified. As well, we found higher outflowing stoichiometric ratios for DOC:TDN and DOC:TDP. This indicates an enrichment of C compared to N and P and suggests biogeochemical processes may be occurring in SWMPs. Overall, our results demonstrate that SWMPs are complex aquatic systems, and we need to consider biogeochemical processes in our design and maintenance activities, so that the effectiveness of SWMPs is not compromised during low flow conditions as a result of internal nutrient releases.

Author Keywords: Carbon, Nitrogen, Phosphorus, Urban biogeochemical cycling, Urban stormwater pond

This thesis investigates the organization and development of water management systems in a sample of past tropical societies in Southeast Asia and Mesoamerica. A comparative approach is employed to show how water management affected the trajectories of the ancient states of Angkor, Cambodia, Bagan, Myanmar, Sukhothai, Thailand, Central and East Java, and Caracol, Belize. Differing types of water management is demonstrated through the use of the adaptive cycle, a conceptual framework through which a broad range of socio-ecological data can be examined in order to explore shifting levels of resilience over time. To understand why levels of resilience might change over time, entanglement theory, which looks at the relationships between humans and things, is utilized to determine how entangled these societies were with water management. Particular degrees of entanglement and shifting levels of resilience provide the analysis with the means to explore how water management changed over time as these societies rose, grew, and finally collapsed.

Author Keywords: Ancient Tropical Societies, Entanglement, Resilience, Socio-Ecological Dynamics, Southeast Asia, Water Management

This thesis aimed to determine what factors influence individual- and community-level shoreline stewardship attitudes and behaviours. Shoreline stewardship is part of the broader literature of environmental stewardship and place-based conservation. The needs and barriers limiting stewardship action were examined, as were the opportunities for increased impact. The Love Your Lake (LYL) program served as a case study into the impact of ENGO programming on shoreline stewardship among shoreline property owners in Ontario. This was investigated using a program workshop, interviews and focus groups with past program participants, and existing participant survey data. Community-Based Social Marketing principles were used to further examine the opportunities for increased impact on stewardship behaviour. The study found that the LYL program was effective in starting or continuing a conversation in communities around shoreline health. Some of the remaining needs and/or barriers included limited time at the cottage; limited knowledge of how to fix existing shoreline issues; low stock of local native plants and environmentally minded landscapers; ineffective messaging; a lack of interest, enthusiasm or concern; and weak environmental policies and governance of shorelines. Some participants also listed cost as a barrier, while others felt it had been well addressed already. Most participants thought that education could be a barrier but that it had been well addressed locally through LYL or other programming. Some key motivators and opportunities to increase shoreline stewardship included community building, increased lake association capacity, improved communication and marketing strategies, and persistence.

Author Keywords: Community-Based Social Marketing, Environmental Stewardship, Lake Health, Place-Based Conservation, Pro-Environmental Behaviour, Shoreline Stewardship

Recent agricultural land use change in east-central Ontario, including the expansion of intensive agriculture (corn and soybean crops) and tile drainage (TD) infrastructure, may alter the fluxes of both phosphorus (P) and nitrogen (N) to the Lower Great Lakes. Through intensive monitoring of several sub-watersheds that encompassed a range of row crop and TD extents, this study examined differences in stream N and P concentrations both seasonally and during variable flow conditions, to better understand land use/land cover (LULC) relationships with nutrient export. There was no clear relationship between total P (TP; concentration or export) and agricultural LULC, and instead, TP delivery was highly sensitive to flow events, and TP concentrations (especially particulate P; PP) were significantly higher during event flow compared with baseflow. In contrast, the dissolved fraction of P (total dissolved P; TDP) and dissolved nitrogen as nitrate (NO3-N) were not sensitive to flow, but were instead positively related to row crop agriculture, and associations between NO3-N concentrations/export and tile-drained row crop area were particularly strong (concentration r2 = 0.93; export r2 = 0.88). Regression relationships showed that with every 10% increase in row crop area in watersheds, NO3-N and TDP flow-weighted concentrations increased by 0.34 mg/L and 1.5 µg/L, respectively. As well, the same 10% increase in row crop agriculture translated to an increase of NO3-N export of as much as 130 kg/km2. Geospatial records of TD are incomplete in east-central Ontario, which presents challenges for evaluating the contribution of TD to nutrient export. Understanding the response of nutrients to changes in agriculture and agricultural practices is an integral part of watershed management as rapid changes in both urban and agricultural LULC continue to put pressure on water quality in the Lower Great Lakes.

Author Keywords: East-Central Ontario, Nutrient Export, Row crops, Streams, Tile Drainage, Water Quality

Changes in climate and land-use practices are leading to higher peak flows and increased transport capacity of channel substrate. Semi-alluvial streams underlain by bedrock or clay were examined to understand the potential impacts of alluvium loss on the biological community and overall productive capacity of semi-alluvial rivers. More specifically, this research investigates the productivity of gravels, bedrock, and consolidated clay, through the biomass and density of periphyton, coarse particulate organic matter, benthic invertebrates, and fish. The ecological approach undertaken demonstrates the relationships among each trophic level and linkages to productive capacity between different substrate types. Significant results were detected at the stream type level and substrate level. Bedrock-based streams were overall more productive in terms of CPOM, biomass and density of benthos in comparison to clay-based streams. Stream reaches with small to large areas of exposed bedrock or clay at the site level did not differ to areas with 100% gravel coverage in the comparison of any variable, including stream fishes. At the substrate level, gravels demonstrated the highest productive capacity in comparison to bedrock and clay substrates. CPOM biomass in gravels compared to bedrock and clay at a ratio of 30:14:1, respectively. Biomass of benthic invertebrates also demonstrated a higher productivity on gravels with a ratio of 59:19:1 in comparison to bedrock and clay, respectively. Positive relationships between CPOM and benthic invertebrate biomass were detected in both stream types.

Relationships were also detected between fish biomass and benthic invertebrate biomass. Examination of benthic fishes also demonstrated positive relationships with benthic invertebrate biomass and density. Clay substrate on all accounts supported little biota. Results indicate alluvium loss in clay bed streams could reduce productive capacity. Understanding and integration of the potential impacts of alluvium loss would aid management and No Net Loss compensation plans to protect fisheries resources in semi-alluvial streams.

This research explores the obstacles Jordan is facing regarding the sustainable treatment and reuse of wastewater in the agricultural sector. It assesses the technical, socio-cultural, and political aspects of decision-making around water and wastewater management in Jordan by focusing on a case study involving wastewater usage in the Jordan Valley. It includes a literature review and interviews with representatives of key stakeholders. While at one level wastewater treatment is a technical process with technological solutions, a nuanced understanding of the non-technical challenges facing the wastewater treatment sector in Jordan is necessary. These challenges are inherently embedded in and contextualized by a series of historical, complex and dynamic political and socio-cultural issues involving stakeholders at local and national levels. Only through an interdisciplinary approach with real stakeholder engagement will meaningful solutions to these challenges be developed and implemented, and at least a portion of Jordan's water needs be meaningfully addressed.

Author Keywords: Agriculture, Jordan Valley, Political challenges, Sociocultural challenges, Technical challenges, wastewater management

Microcontaminants originating from wastewater effluent and run-off from agricultural lands may be present in the sources of drinking water for rural and Indigenous communities in mixed-use watersheds. In this study, a convergent parallel mixed-methods design was applied to assess measured and perceived risks of contamination in the sources of drinking water for two communities; the Six Nations of the Grand River community in Ontario and the community of Soufriere in St. Lucia, West Indies. The overall goal of the project was to assess how measured and perceived risks of exposure to chemical and biological contaminants in drinking water sources could inform water management strategies for the communities. Quantitative data obtained from the analysis of water samples collected indicated that the highest levels and occurrence of fecal bacteria were found in the Soufriere watershed while the highest concentrations and occurrence of pesticides were found in the Grand River watershed. In the Grand River watershed, conventional treatment of water followed by activated carbon filtration and UV disinfection removed fecal bacteria and also removed many chemical microcontaminants with efficiencies as high as 98%. Data from both watersheds indicated that there was a strong positive correlation between the levels of caffeine and sucralose (i.e. indicators of wastewater contamination) in water samples and the levels of either Total Coliforms or fecal bacteria of human origin. Human health risk assessments of individual pesticides and pesticide mixtures performed by applying a hazard quotient (HQ) and hazard index (HI) model, respectively indicated that there were no apparent risks to human health from those microcontaminants. Qualitative data obtained from face-to-face interviews with water managers and health professionals working in the two communities, which were collected and analysed concurrently but independently, illustrated that there were cross-cultural similarities and differences in factors influencing the perceptions of risks associated with the sources of drinking water. These perceptions of risks were mainly influenced by factors such as heuristics or informal and informal reasoning, cognitive-affective factors, social-political institutions and cultural factors. These factors may have also influenced water managers and health professionals, as they often recommended more "soft" strategies for managing water resources in the communities.

Key words: pesticides, fecal bacteria, microcontaminants, POCIS, measured risks, perceived risks, water management, First Nations, Grand River, Soufriere, St. Lucia

Author Keywords: fecal bacteria, measured risks, microcontaminants, perceived risks, POCIS, water management

Water balance models calculate water storage and movement within drainage basins, a primary concern for many hydrologists. A Thornthwaite water balance model (H2OBAAS) has shown poor accuracy in predicting low flows in the Petawawa River basin in Ontario, so lake storage and winter snow processes were investigated to improve the accuracy of the model. Lake storage coefficients, represented by the slopes of lake stage vs. lake runoff relationships, were estimated for 19 lakes in the Petawawa River basin and compared on a seasonal and inter-lake basis to determine the factors controlling lake runoff behaviour. Storage coefficients varied between seasons, with spring having the highest coefficients, summer and fall having equal magnitude, and winter having the lowest coefficients. Storage coefficients showed positive correlation with lake watershed area, and negative correlation with lake surface area during summer, fall, and winter. Lake storage was integrated into the H2OBAAS and improved model accuracy, especially in late summer, with large increases in LogNSE, a statistical measure sensitive to low flows. However, varying storage coefficients with respect to seasonal lake storage, watershed area, and surface area did not improve runoff predictions in the model. Modified precipitation partitioning and snowmelt methods using monthly minimum and maximum temperatures were incorporated into the H2OBAAS and compared to the original methods, which used only average temperatures. Methods using temperature extremes greatly improved simulations of winter runoff and snow water equivalent, with the precipitation partitioning threshold being the most important model parameter. This study provides methods for improving low flow accuracy in a monthly water balance model through the incorporation of simple snow processes and lake storages.

Author Keywords: Lake Storage, Model Calibration, Monthly Water Balance, Petawawa River, Precipitation Partitioning, Snow Melt

Lake of the Woods (LOW) is a large international waterbody which suffers from frequent and widespread algae blooms. Previous studies have highlighted the importance of the lake's largest tributary, the Rainy River (RR) and its significance in total phosphorus (TP) delivery to the LOW. Unfortunately, little is known about TP contributions from the RR and its tributaries within the Canadian portion of the watershed. This thesis examines patterns and sources of TP from four tributaries on the Canadian side of the lower RR region, two of which are predominantly natural, and two that are predominantly agricultural. Relationships between water quality parameters, land use and geologic characteristics were observed over a complete hydrologic year (Oct 1, 2018 - Sept 31, 2019), and through an intensive sampling campaign using a nested watershed approach during the spring high flow and summer low flow periods. Results revealed that TP and total suspended sediment (TSS) concentrations (>100 µg/L and >20 mg/L respectively), and loads (>20 kg/km2 and >3500 kg/km2, respectively), were greater at agricultural sites compared with natural sites (<65 µg/L TP and <15 mg/L TSS concentration, and <20 kg/km2 TP and <4000 kg/km2 TSS export). Total P, TSS, Fe, and Al were significantly positively correlated (R2= 0.26-0.59; p<0.05) and intensive sampling revealed that these relationships were strongest during the spring and at the agricultural sites (R2= 0.73-0.98; p<0.05). In contrast, the summer intensive sampling revealed that TP and redox sensitive Fe were significantly correlated (R2= 0.72; p<0.005), whereas redox insensitive Al and TSS were not, suggesting TP may be sourced via redox processes in the summer due to favourable hydrologic conditions. This was observed not only at sites with high wetland influence, but also at sites with more agricultural presence suggesting that redox sourced TP may also originate from mineral stream bed sediment during low flow periods. This research suggested two primary TP sources in the lower RR region: erosion in the spring, and redox processes (internal release) in the summer. It is recommended that intensive monitoring continue in Canada, and further research be conducted to fully understand the significance of internal P release in the tributaries.

Author Keywords: erosion, land use, nutrients, particulates, redox, water quality