scholarly journals Evaluating Mismatches between Legislation and Practice in Maintaining Environmental Flows

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2135
Author(s):  
Jessica Chappell ◽  
Laura German ◽  
S. Kyle McKay ◽  
Cathy Pringle

Freshwater is essential to human communities and stream ecosystems, and governments strive to manage water to meet the needs of both people and ecosystems. Balancing competing water demands is challenging, as freshwater resources are limited and their availability varies through time and space. One approach to maintain this balance is to legally mandate that a specified amount of stream flow be maintained for stream ecosystems, known as an environmental flow. But laws and regulations do not necessarily reflect what happens in practice, potentially to the detriment of communities and natural systems. Through a case study of Puerto Rico, we investigated whether water management in practice matches legislative mandates and explored potential mismatch drivers. We focused on two governance targets—equitable allocation and water use efficiency—and assessed whether they are enshrined in the law (de jure) and how they manifest in practice (de facto). We also explored agency accountability through identifying agency structure and whether consequences are enforced for failing to carry out responsibilities. Our results indicate there are mismatches between how freshwater is governed by law and what occurs in practice. This study suggests that agency accountability may be necessary to consider when developing environmental flow legislation that will effectively achieve ecological outcomes.

Author(s):  
Laureline Berthot ◽  
André St-Hilaire ◽  
Daniel Caissie ◽  
Nassir El-Jabi ◽  
Judith Kirby ◽  
...  

Abstract Through a case study in Southern Quebec (Canada), the assessment of environmental flows in light of the effects of climate change is investigated. Currently, the 7Q2 flow metric (7-day average flow with a 2-year return period) is used for water abstraction management. Several flow metrics were calculated using flow time series simulated by a deterministic hydrological model (HYDROTEL) and climate change scenarios as inputs. Results were compared within homogeneous low flow regions defined using ascendant hierarchical clustering, for the 1990, 2020 and 2050 horizons and annual, summer and winter periods. The impact of each flow metric on the potential availability of physical habitat was analyzed using the wetted perimeter as a proxy. Results indicated that: (1) the increasing non-stationarity of simulated flow data sets over time will complicate the use of frequency analysis to calculate the 7Q2 flow metric; (2) summer low flow values are expected to be lower than winter low flows; and (3) flow-duration curve metrics like the LQ50 (median discharge value of the month with the lowest flow) may become relevant environmental flow metrics by 2050. Results question current water abstraction management tools and permit to anticipate future local and regional issues during low flow periods.


Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1800 ◽  
Author(s):  
Liu Zhang ◽  
Buxian Yuan ◽  
Xinan Yin ◽  
Yanwei Zhao

Previous research on environmental flows (e-flows) of urban rivers usually assumes that the channel morphology is fixed. However, due to the trapping of sediments by weirs, the channel morphology will undergo significant changes. In this research, the influence of channel morphological changes on e-flow requirements is explored in urban rivers. The hydrological connectivity is considered as a primary factor in e-flows, and three hydrological connectivity scenarios (i.e., high, medium, and low) are explored. The Shiwuli River is adopted as the case study. The results show that e-flows are significantly influenced by changes in river morphology. With an increase in siltation depth, the e-flow requirements will decrease. The sensitivity of e-flows to siltation varies among different river segments, especially in those with low weir heights. In addition, the change ratios of e-flows are different under different hydrological connectivity scenarios. Although siltation is beneficial to the satisfaction degree of e-flow supply, it also leads to a decrease in the flood control ability of rivers. The balance between e-flow and flood reduction is also discussed, and river segments are identified that should be the priority when adopting dredging measures.


2021 ◽  
Author(s):  
Avril Horne ◽  
J Webb ◽  
Meghan Mussehl ◽  
Andrew John ◽  
Libby Rumpff ◽  
...  

Adaptive management has become the preferred approach for managing environmental flows globally, and successful implementation recognizes multiple dimensions of variability and complexity in socio-ecological systems. This paper outlines an environmental flow assessment methodology that explicitly addresses the uncertainty and change inherent in adaptively managing multiple values for management of environmental flows. While non-stationarity and uncertainty are well recognised in the climate literature, these have not been addressed within the structure of environmental flows methodologies. Here, we present an environmental flow assessment that is structured to explicitly consider future change and uncertainty in climate and socio-ecological values, by examining scenarios using ecological models. The environmental flow assessment methodology further supports adaptive management through the intentional integration of participatory approaches and the inclusion of diverse stakeholders. We present a case study to demonstrate the feasibility of this approach, highlighting how this methodology facilitates adaptive management. Rethinking our approach to environmental flows assessments is an important step in ensuring that environmental flows continue to work effectively as a management tool under climate change.


2013 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Orphanopoulos Damaris ◽  
Verbist Koen ◽  
Chavez Alvaro ◽  
Soto Guido

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