Socio-Ecological Regionalization of the Urban Sub-Basins in Mexico

Targeting Irrigation Expansion to Address Sustainable Development Objectives: A Regional Farm Typology Approach

Sustainable water management is a core sustainable development goal (SDG) that also contributes to other SDGs, including food and water security, ecosystem health, and climate adaptation. To achieve these synergies, policies must target efforts to regions that best correspond with development objectives. This study designs a targeting strategy for irrigation expansion in southern Mexico—a region long considered to have strong potential for sustainable irrigation development. We use an integrated farm typology and decision tree approach to identify priority municipalities for irrigation expansion. We use multivariate statistics to examine the relationships among farm characteristics in 933 municipalities, classifying each according to four farm types: lowland, midland, midland-irrigated, and highland. We then partition municipalities into 11 farm-type subgroups, each ranked by priority level for receiving irrigation interventions following Mexico’s National Water Program guidelines. Results identify a ‘highest-priority’ subgroup of 73 municipalities comprised mostly of midland and highland farm types. These types are characterized by low irrigation use, small farmland areas, high vulnerability to climate, high marginalization (poverty), strong representation from indigenous communities, low maize yield, and high rates of subsistence production. Findings provide a crucial first approximation of where irrigation expansion would best address water policy priorities and sustainable development objectives in southern Mexico. This study also provides a useful framework for scaling organizations tasked with targeting development efforts across large spatial scales.

Framework of multi-level regionalization schemes based on non-point source pollution to advance the environmental management of small watersheds

Regionalization exerts an important guiding role for sound environmental management, regional development, and schemes toward regionalizing ecological function, involving multiple levels. This paper formulated a framework for a detailed regionalization approach using the Ashi River watershed, China, as case study. Human activities, especially agriculture non-point source pollution (ANPS) and social factors, were identified as main factors. The results indicated that (1) the export coefficient model (ECM) can be used to determine ANPS loads in the watershed as well as total nitrogen and total phosphorus loads. (2) The minimum cumulative resistance model (MCR) showed that the middle and lower reaches had high risk for ANPS occurrence. (3) Based on the identified key factors, the watershed was divided into level IV and combined with existing level III using cluster analysis. Corresponding management countermeasures were proposed. This provides a scientific basis for pollution control planning and for management measures.

A baseline assessment of hydrologic alteration degree for the Mexican catchments at gauged rivers (2016)

River regime has been modified in several freshwater bodies around the world. This alteration has led to species loss, water pollution, higher or lesser economic profits, changes in magnitude, timing, duration and rate change of flow, among others. Thus, hydrologic alteration assessment allows evaluating the regime parameters so that stakeholders, decision-makers, and dams managers may take efficient actions to mitigate or rehabilitate riparian ecosystems. In the present study, Hydrologic Alteration Indexes on Rivers (IAHRIS, for its acronym in Spanish) and the Mexican standard approach were considered to evaluate 1150 gauged catchments in Mexico and come up with an alteration baseline for 67.03% of the country surface. The comparison may assist stakeholders to propose potential changes in the Mexican standard approach. Results reveal that 232 analyzed catchments can be considered as non-altered according to IAHRIS. In stark contrast, there are 281 non-altered catchments in Mexico in agreement with the official standard approach. Altered catchments are mainly impacted by minimum flow metrics and connectivity discharge. Additionally, the correlation between alteration indexes and 5 socio-economic variables was checked to identify which variables may greatly impact hydrologic alteration evolution or mitigation. From the five selected variables, the Human Development Index is significatively correlated to extreme minimum metrics (p = 0.94) while the Gross Domestic Product to extreme maximum metrics (p = 0.90).