Basic tools for setting environmental flows at the regional scale: application of the ELOHA framework in a Mediterranean river basin

Abstract

Ecological limits of hydrological alteration (ELOHA) framework aims to set limits of hydrologic alteration based on empirical hydroecological relationships built along flow impairment gradients. These relationships can be specific for different natural flow regime types. The object of our study is testing the ELOHA method in the Ebro River Basin. Seven flow alteration–ecological response curves were obtained in the present study as preliminary guidelines for developing and calibrating environmental flow standards in the Ebro River Basin. For continental Mediterranean‐pluvial flow regime mean monthly flow in March was related to Plecoptera abundance (ELOHAs ±21% from baseline), and high flow magnitude and frequency were closely related to Plecoptera, Ephemeroptera and Trichoptera richness (ELOHAs for high flow magnitude and frequency were +18 and +54% the reference central value respectively). For nivo‐pluvial flow regime, high flow magnitude was found indicative of macroinvertebrate biodiversity and Coleoptera abundance (ELOHAS −12 and +23% from central reference value respectively). And for pluvio‐oceanic flow regime, mean monthly flow in January was indicative of the proportion of Gastropoda, Oligochaeta and Diptera taxa (GOLD index) (ELOHA +17% from baseline). These hydrological limits are endorsed by recent international reference works. Flow alteration–ecological relationships presented here were constructed from real monthly flow data records and macroinvertebrate samples at family level. ELOHA values obtained in this study pretend to be a starting point for implementing an environmental flow regime program in the Ebro River Basin. Copyright © 2016 John Wiley & Sons, Ltd.

Application of regional flow‐ecology relationships to inform watershed management decisions: Application of the ELOHA framework in the San Diego River watershed, California, USA

“…These sites had Application of the regional flow-ecology relationships to local management scenarios revealed several complications associated with the formulations of certain commonly used metrics (Solans & Jalon, 2016). In particular, they highlight the types of sites where regional models work best, and where they are prone to misinterpretation.…”

“…Developing the regional flow-ecology relationships and applying them at the local scale would not have been possible without the regional bioassessment data and the existence of the predictive scoring tool (Mazor et al, 2016). Large regional data sets provide sufficient sample size to develop statistically meaningful flowecology relationships in spite of the inherent "noise" in the data associated with other co-occurring factors that interact with flow to affect biological community condition (Solans & Jalon, 2016 • NoDisturb (days) is the median annual longest number of consecutive days that flow is between the low (Q10) and the high flow (Q90) threshold. Disturbance changes the bed shear stress and effects sediment transport.…”

“…McManamay, Orth, Dolloff, and Mathews (2013) applied ELOHA through a case study in North Carolina to assess the effect of a stream restoration on fish and riparian communities. Solans and Jalon (2016) used a series of flow alteration-ecological response curves to develop environmental flow standards for the Ebro River Basin in the Iberian Peninsula. The Nature Conservancy has developed ecosystem flow recommendations for the Susquehanna River Basin (DePhilip & Moberg, 2010) and the upper Ohio River Basin (DePhilip & Moberg, 2013) using elements of the ELOHA framework in a qualitative manner that provide seasonally differentiated targets for different stream classes and multiple biological endpoints (e.g., fish, mussels, amphibians, and vegetation).…”

Putting Flow–Ecology Relationships into Practice: A Decision-Support System to Assess Fish Community Response to Water-Management Scenarios

“…The Ecological Limits of Hydrologic Alteration (ELOHA) [31] is commonly cited as a general framework for discerning flow-ecology relationships, but it provides little guidance on how these relationships can be operationalized to support specific and localized water-management decisions. For example, recent applications of the ELOHA framework have either produced flow-ecology relationships [36][37][38][39] or have prescribed general flow standards for particular river systems [40,41] but have not provided objective, quantitative frameworks for translating particular water-management decisions (e.g., withdrawal permits, and dam releases) into predicted hydrologic or ecological outcomes. Although substantial science exists on ecological effects of flow alteration [16,42], this understanding is often not specific enough to be readily translated into usable DSS [17], such that the "implementation" phase of ELOHA (lower left corner of figure 1 in [31]) remains a challenge.…”

Quantitative Assessment of Flow Regime Alteration Using a Revised Range of Variability Methods

“…Therefore, the accurate determination of flow regime alteration is vital to the design of environmental flow for ecosystem restoration [4]. The Ecological Limits of Hydrologic Alteration (ELOHA) framework, which focuses on the analysis of flow alteration, has been widely used to determine and implement environmental flows [5] at regional scales [6][7][8]. Therefore, an effective method for assessing flow regime alteration is required to successfully implement the ELOHA framework [9].…”