Sustainability assessment of agricultural rainwater harvesting: Evaluation of alternative crop types and irrigation practices

Holistic Sustainability Assessment of Riparian Buffer Designs: Evaluation of Alternative Buffer Policy Scenarios Integrating Stream Water Quality and Costs

Riparian buffer zones (RBZs) have been shown to be effective best management practices (BMPs) in controlling non-point source pollutants in waterbodies. However, the holistic sustainability assessment of individual RBZ designs is lacking. We present a methodology for evaluating the holistic sustainability of RBZ policy scenarios by integrating environmental and economic indicators simulated in three watersheds in the southeastern USA. We developed three unique sets of 40, 32, and 48 RBZ policy scenarios as decision management objectives (DMOs), respectively, in Back Creek, Sycamore Creek, and Greens Mill Run watersheds (Virginia and North Carolina) by combining the RBZ-widths with vegetation types (grass, urban, naturalized, wildlife, three-zone forest, and two-zone forest). We adapted the RBZ-hydrologic and water quality system assessment data of instream water quality parameters (dissolved oxygen, total phosphorus, total nitrogen, total suspended solids-sediment and biochemical oxygen demand) as environmental indicators, recently published by U.S. EPA. We calculated 20-year net present value costs as economic indicators using the RBZ's establishment, maintenance, and opportunity costs data published by the Natural Resources Conservation Service. The mean normalized net present value costs varied by DMOs ranging from 4% (grass RBZ-1.9 m) to 500% (wildlife RBZ-91.4 m) across all watersheds, due primarily to the width and the opportunity costs. The mean normalized environmental indicators varied by watersheds, with the largest change in total nitrogen due to urban RBZs in Back Creek (60-95%), Sycamore Creek (37-91%), and Greens Mill (52-93%). The holistic sustainability assessments revealed the least to most sustainable DMOs for each watershed, from least sustainable wildlife RBZ (score of 0.54), three-zone forest RBZ (0.32), and three-zone forest RBZ (0.62), respectively, for Back Creek, Sycamore Creek, and Greens Mill, to most sustainable urban RBZ (1.00) for all watersheds.

Formulation of Water Sustainability Index for India as a performance gauge for realizing the United Nations Sustainable Development Goal 6

Anthropogenic activities targeting economic progress have triggered changes in the Earth system processes causing depletion of resources and degradation of ecosystems. Water is a critical natural resource which has been severely impacted through groundwater depletion, surface water contamination and ocean acidification resulting in repercussions on human health and biodiversity losses. Likewise, India, a mega biodiversity nation has been critically affected by degradation and drawdown of water resources with far-reaching consequences on environmental vitality and socio-economic development. In order to prevent extreme water scarcity in the near future, the country needs to promote sustainable utilisation of water resources by adhering to the targets of Goal 6 of the United Nations Sustainable Development Goals (UN-SDGs). The present work, therefore, has focussed on the development of a Water Sustainability Index (WSI) for India that would help attaining the targets of SDG 6. A total of 12 indicators categorized under biophysical and social development dimensions and synonymous with the targets of SDG 6 have been used for the formulation of WSI and thereby understanding how much water resources are used annually in a sustainable manner. The study also highlights the interrelationship between the diverse social development and health indicators (SDG 3) of Indian community. The research has the potential to provide guidance for efficient use of water resources in India. Acting as a yardstick and guiding star, the sustainability metric will help the nation to monitor whether it is on the right track and navigate its journey towards achieving water sustainability. It also calls for cautious course correction and restructuring of current Indian policy and operational instruments for effective green governance and sustainable water management.

Generation of Potential Sites for Sustainable Water Harvesting Techniques in Oum Zessar Watershed, South East Tunisia

Water harvesting techniques (WHTs) are important climate change adaptation measures to better manage rainwater for domestic and agricultural purposes, but which WHT to plan where is subject to sustainability considerations. Moreover, suitability of different WHTs varies from one location to another, depending on physical and socio-economic conditions. This study aimed to identify suitable sites for WHTs taking into account stakeholders’ sustainability criteria. In a participatory assessment framework, Geographic Information Systems and the “Simple Multi-Attribute Rating Technique” were combined to generate suitability maps and to guide sustainable WHTs investments. Steps included the calculation of a sustainability index for a set of traditional and newly introduced WHTs from the perspective of two stakeholder groups, farmers and decision-makers, and its integration with layers of biophysical constraints. An application of the framework in the Oum Zessar watershed, southeast Tunisia, shows that traditional techniques are the most suitable and sustainable for farmers and fall within the highly suitable class in 76.4% of the total area, while decision-makers prefer innovative techniques that are highly suitable in 80.4% of the watershed. The framework offers a scalable transparent process for knowledge integration in support of WHT investment decisions that can be adapted to other dryland areas.

Sensitivity of Riparian Buffer Designs to Climate Change-Nutrient and Sediment Loading to Streams: A Case Study in the Albemarle-Pamlico River Basins (USA) Using HAWQS

Riparian buffer zones (RBZs) provide multiple benefits to watershed ecosystems. We aimed to conduct an extensive sensitivity analysis of the RBZ designs to climate change nutrient and sediment loadings to streams. We designed 135 simulation scenarios starting with the six baselines RBZs (grass, urban, two-zone forest, three-zone forest, wildlife, and naturalized) in three 12-digit Hydrologic Unit Code watersheds within the Albemarle-Pamlico river basin (USA). Using the hydrologic and water quality system (HAWQS), we assessed the sensitivity of the designs to five water quality indicator (WQI) parameters: dissolved oxygen (DO), total phosphorous (TP), total nitrogen (TN), sediment (SD), and biochemical oxygen demand (BD). To understand the climate mitigation potential of RBZs, we identified a subset of future climate change projection models of air temperature and precipitation using EPA's Locating and Selecting Scenarios Online tool. Analyses revealed optimal RBZ designs for the three watersheds. In terms of watershed ecosystem services sustainability, the optimal Urban RBZ in contemporary climate (1983-2018) reduced SD from 61-96%, TN from 34-55%, TP from 9-48%, and BD from 53-99%, and raised DO from 4-10% with respect to No-RBZ in the three watersheds. The late century's (2070-2099) extreme mean annual climate changes significantly increased the projected SD and BD; however, the addition of urban RBZs was projected to offset the climate change reducing SD from 28-94% and BD from 69-93% in the watersheds. All other types of RBZs are also projected to fully mitigate the climate change impacts on WQI parameters except three-zone RBZ.

Reliability and financial feasibility assessment of a community rainwater harvesting system considering precipitation variability due to climate change

This study proposes a community rainwater harvesting (RWH) system as an alternative water supply solution for Paikgacha, a water-scarce coastal urban area in Bangladesh. Although individual household-based RWH systems have been implemented in many areas in Bangladesh, to date, no study has been conducted designing a community RWH system and assessing its reliability and financial feasibility. This study employs historical observed and available climate model predicted future rainfall data into stormwater management model (SWMM) for rainfall-runoff simulation of the community RWH, and compares SWMM's performance with rational formula based estimation. We then calculate volumetric and time reliability of the proposed system and assess its financial viability. We observe good agreement in reliability curves generated by SWMM and rational formula-based model. Under the historical rainfall scenario, our proposed community RWH shows up to 99% reliability for 100 L per day household demand, given that proper community size and storage tank size are chosen. Predicted rainfall pattern of 2041-2070 period shows similar reliability-tank size relation to that of historical observed rainfall; however, predicted high precipitation intensity during 2021-2040 and 2071-2100 seem to assist the system in attaining higher reliability. Cost-benefit analysis indicates the financial viability of the proposed system. Finally, we develop a nomograph incorporating interactive factors of RWH, which would ease decision making by the policymakers regarding the implementation of community RWH.