“Index of Watershed Integrity (IWI) of a Central Mexican Plateau microwatershed: An instrument of environmental governance”

Abstract

Watershed management must be prioritized in Mexico due to environmental degradation. To address the issue, an instrument to assess watershed functional status and specific governance conditions is needed. We assessed the functional conditions of a microwatershed (a watershed of less than 5000 ha) located in the headwater of the Querétaro River watershed using the Index of Catchment Integrity (ICI) to evaluate local conditions and the Index of Watershed Integrity (IWI) to evaluate the cumulative conditions. Implementing the IWI in La Laborcilla Microwatershed (LMW) required some adaptations to the available information. We integrated data generated through two indices: The Environmental Water Quality Index (EWQ(i)), which evaluates the physicochemical conditions of water from an ecosystem perspective, and the Hydrogeomorphological Index (IHG), which assesses the conditions of naturalness or alteration of riparian ecosystems. These complementary indices generated detailed information on the stressors that affect the six functional components of the watershed. To complete the assessment, we evaluated the LMW management process within local decision-making and policy instruments. The watershed had medium-low integrity (IWI=0.43). The integrity of the catchments (ICI) spanned from 0.27 to 0.58. Watershed integrity is a relevant perspective for effective watershed management in operational forms within the territorial planning process and environmental policy instruments.

INTRODUCTION

The biophysical degradation of watersheds in Mexico results from climate change, increasing water demand related to population growth, urbanization, and intensification of industrial, agricultural, livestock, and aquaculture production, among other factors (UNESCO-ONU, 2020). Through spatial multi-criteria analysis and variables related to river fragmentation, riparian zone degradation, and diffuse potential contamination, among others, Cotler et al. (2010) estimated that 66% of Mexico’s watersheds have a high degree of deterioration, causing 81% of the human population to be at environmental risk. The water stress is compounded by insufficient environmental governance for successful management and conservation of watersheds (Cotler-Ávalos, 2020). Watershed degradation constitutes a historical problem; for example, in the Mirador-Calakmul Watershed, overconsumption of natural resources has precipitated human-induced deforestation and consequential negative environmental repercussions. This has, in turn, weakened the agricultural system, fostering an unsustainable socio-environmental state. Significantly, this state of affairs has been identified as a principal factor contributing to the collapse of the Maya culture, as documented by Hansen (2011).

The concerns identified above are addressed from the perspective of watershed integrity in the development of our analysis. Watershed integrity relates to a systematic perspective implicit in various conceptual proposals regarding natural systems. Karr (1996) defines biological integrity as the capacity to sustain a balanced, integrated, and adaptive biological system, encompassing all its elements and expected processes in the habitat of a region. Specifically, watershed integrity refers to the condition and capacity of the watershed to maintain the full range of functions and processes necessary to sustain its physical structure and the biodiversity it harbors, as well as the flow of services provided in social terms (Flotemersch et al., 2015).

Watershed integrity degradation is not only visible and addressable on the nationwide side, but it is also a phenomenon equally measurable in the local context; in this case, our study was conducted in the La Laborcilla Microwatershed (LMW) located at the headwater of Querétaro River watershed in the State of Querétaro. Regarding the terminology used to identify this area, a microwatershed, considering the Mexican official nomenclature, is described as a watershed with an area equal to or less than 5000 hectares, while a subwatershed is a watershed between 5,000 and 50,000 ha according to the Mexican Institute of Water Technology (IMTA, 2019).

The Querétaro River is a lotic ecosystem that flows through several dispersed small towns in different municipalities and the Metropolitan Zone of Querétaro (ZMQ). The river receives pollutants from direct discharges of urban and industrial wastewater and diffuse discharges from agricultural activity that contribute pollutants to the local hydrological system (Cortés-Silva et al., 2009; Hernández-Pérez et al., 2022; Hernández-Vargas, 2020). These residual discharges then degrade water quality, increasing health risks for local human populations while also causing significant alterations to water quality, biodiversity loss, and changes in structure and morphology. Additionally, the river exhibits fragmentation and changes in structure and morphology, associated with urbanization, land-use changes, and other modifications, altering its natural state. (SEDESU, 2020).

The degradation of watersheds and water supply problems are related closely to the challenges of governance, environmental policy, and territorial management in watersheds in México (Vargas and Mollard, 2005). There is a lack of coordination and cooperation between government authorities and local stakeholders, hindering effective policy implementation (Pineda-Lopez et al., 2007). Additionally, the lack of environmental justice, reflected in financial, technical, and legislative deficiencies, limits the government’s capacity to address these problems comprehensively. As a result, biodiversity loss and environmental degradation have intensified due to the unsustainable use of ecosystem functions and the limited participation of citizens in decision-making regarding watershed management in Mexico. (Cotler-Ávalos and Pineda-López, 2008).

We conducted an analysis that objectively evaluated the integrity conditions of the Laborcilla microwatershed. The study site location and its characteristics allowed us to assess watershed integrity as a comparative exercise between the natural, unaffected areas in the headwaters and its degradation through the anthropogenically affected areas. The framework of the Index of Watershed Integrity (IWI; Flotemersch et al., 2015) was applied to conduct the exercise. This analysis uses the IWI and the ICI to assess six key watershed functions, considering anthropogenic stressors like land use and stream-road crossings, all combined into a single index that reflects overall watershed integrity. The ICI complements the IWI by focusing on local catchment-scale processes. While a watershed includes all upstream influences, a catchment refers only to the local contributing area. Both indices range from 0 to 1, providing a detailed view of watershed conditions. Because the methodologies are very similar, whenever the IWI is mentioned, it also implicitly refers to the ICI. This index has not been previously applied at the microwatershed scale in México. Due to the scarcity of biophysical data and the spatial scale of work in LMW, the assessment required a methodological adaptation to gather and integrate the information necessary for the analysis. These modifications generate an adequate knowledge of the environmental conditions and provide the authorities and decision-makers with a valuable instrument to solve the governance needs of this and other watersheds. To gather adequate information, we also proceeded to collect and process in situ data to generate the Environmental Water Quality Index (EWQ(i)) and the Hydrogeomorphological Index (IHG) as complementary elements (Ollero-Ojeda et al., 2011).

The integration of indicators of different categories not only provided viability to the realization of the IWI in this specific case but also made it possible to obtain finer and more detailed results on the microwatershed’s functional conditions and stressors. This allowed the generation of useful and timely information for proper management in the context of environmental governance of LMW. To complement this assessment and better understand governance in LMW, a series of decision-maker interviews were conducted to analyze how watershed integrity relates to decision-making processes.

Conceptual Foundations and Frameworks for Watershed-Focused Environmental Governance.

Due to the complexity of the systemic nature of the watershed, an adequate governance viewpoint with multiple theoretical and applied complements is required to adequately integrate the watershed integrity perspective and its relative assessment to a public environmental policy framework and provide factual mechanisms that strengthen the pathway to a truly watershed driven governance process. Establishing clear objectives and providing operative elements to promote a governance model to achieve sustainable watershed management should not be developed in a limiting manner as it is necessary to consider a broader governance thinking and model design approach.

Environmental governance, which draws from ecopolitics or political ecology, deals with “showing that ecological problems result from political problems, institutional functions of power, and social organization” (Pereira-Guimarães, 2011). According to this author, some of the objectives of environmental governance are: 1) Efficiency in addressing environmental changes; 2) Ensuring the integrity of nature’s cycles; 3) Maintaining the flow of the cascade of Ecosystem Services; 4) Promoting the resilience of social systems; and 5) Reversing social asymmetries by promoting equity and equality. To achieve these objectives, from a socially oriented perspective of governance, it is necessary to integrate principles of participation, collaboration, and democracy (Camus, 2012).

A watershed-focused environmental governance is a model of collaboration between government entities and local communities to protect common interests and objectives concerning the watershed. It involves establishing watersheds as governance units to align comprehensive decision-making at the landscape scale, recognizing their interconnection across hydrological, social, economic, and environmental aspects. Local-scale governance is essential as local interests directly intersect with watershed functions through the demand for ecosystem services. To promote effective governance, communities and local governments must understand the importance of watershed functions and structure to utilize information for informed decision-making (Hirokawa, 2012). In this case, it is important to recognize the watershed itself as a device for storing information. According to Margalef (1978), over time, the physical changes resulting from development or human intervention in a material system accumulate information, e.g., the development of meanders in a river or human-induced alterations. Deciphering this information is crucial not only to understand the biophysical conditions of the watershed but also to better comprehend how decision-making has occurred in the past and present and how it should be approached in the future.

From a social-ecological governance perspective, an adaptive co-management approach aligns efforts to achieve societal goals in human-environment interactions. It integrates reflective decision-making and innovation in problem-solving, involves diverse stakeholders, and relies on decision-making networks at different organizational scales. This must be conducted by providing necessary information and infrastructure, ensuring compliance, managing conflicts, and promoting adaptation and change (Kofinas, 2009). Effective environmental governance is essential for maintaining watershed integrity and its stability as a system. A robust governance model is needed to sustain the socio-environmental balance of a watershed, thereby ensuring its stability over time. When environmental governance is weak, scenarios of lack of control arise. Therefore, disruptions such as ecosystem overexploitation, pollution, urbanization, etc., can compromise watershed integrity, potentially leading to instability or collapse. This governance model aims to generate useful processes to constitute a more effective and robust cybernetic system within the socio-ecological framework, aiming to stabilize or restore watershed integrity conditions. To develop this model, in a synthesis of what has been mentioned, in the context of the study zone, and considering some articulating elements, it is important to emphasize the following aspects in particular: 1) Hierarchical watershed governance units; 2) Decision-making based on rigorous information including generation of feedforwards (Lorenzón, 2020); 3) Multiscale role designation and organization process in policymaking and; 4) Diverse stakeholder factual participation with a perspective of citizen power (Arnstein, 1969) through the whole Water Governance Cycle (OECD, 2015).

Finally, it is important to consider the broad perspective of water governance, which can be defined as “the range of political, institutional, and administrative rules, practices, and processes (formal and informal) through which decisions are taken and implemented, stakeholders can articulate their interests and have their concerns considered, and decision-makers are held accountable for water management.” To strengthen and promote a robust governance framework, it is necessary to enrich the proposed model with specific water governance principles and dimensions that are adequate for our study (OECD, 2015) (Table 1).

Table 1.-.

OECD water governance dimensions and principles

Dimension	Principles
Effectiveness	Principle 2 (PR2): Manage water effectively by adapting to local conditions and fostering multi-level cooperation.
Efficiency	Principle 5 (PR5): Update and share water data to guide policies, promoting stakeholder engagement and system harmonization. Principle 7 (PR7): Ensure and enforce clear, transparent water management regulations with adequate resources and incentives for compliance. Principle 8 (PR8): Implement innovative governance practices, strengthening the science-policy interface.
Trust and Engagement	Principle 12 (PR12): Regularly monitor and evaluate water governance, ensuring transparency and responsiveness to feedback

Approaches related to watershed integrity assessment

Diverse governmental and academic institutions have developed and implemented methodologies to assess watershed integrity, aiming to provide valuable information for decision-making and territorial management. These approaches integrate a wide range of indicators, including hydrological, ecological, and landscape variables, to generate a comprehensive understanding of watershed conditions. Some methodologies focus on water quality and pollution loads, while others emphasize habitat connectivity, land-use changes, or ecosystem service valuation. By combining different assessment tools, these frameworks contribute to adaptive management strategies suited to specific territorial contexts. Among these efforts, the Index of Watershed Integrity (IWI) proposed by Flotemersch et al. (2015) emerges as a key reference, providing a scientifically robust framework for diagnosing and quantifying the functional integrity of watersheds with precision and adaptability.

An example of previously developed and relevant watershed assessments includes a 2007 regional study conducted by the U.S. Department of Agriculture’s Forest Service, Rutgers University, the U.S. Geological Survey, and the Regional Plan Association. This study focused on the uplands of New York and New Jersey, applying the operational concept of watershed integrity through a multivariable framework at the landscape scale (Lathrop et al., 2007).

Another approach to evaluating watershed integrity is the Multi-Scale Assessment of Watershed Integrity (MAWI; Lin et al., 2008), which has been applied to five watersheds in southern California and to assess the Russian River watershed in the northern part of the state. This method seeks to establish baseline conditions, evaluate cumulative impacts, and identify priority areas for conservation, restoration, and water resource management. It integrates the interconnectivity and interactions among water bodies, riparian zones, and terrestrial ecosystems to provide a comprehensive assessment. In South Korea, the Watershed Health Index assessed the Han River using the Soil and Water Assessment Tool (SWAT) approach, focusing on hydrological functions and water quality (Ahn and Kim, 2017).

At the national level, in the Valley of Mexico Watershed, the Ministry of Environment and Natural Resources (SEMARNAT) and the Mexican Institute of Water Technology (IMTA) recognized the importance of ecological integrity as a regulatory notion in environmental matters. They conducted an analysis of hydroecological integrity with five thematic axes: 1) Water quality; 2) Surface hydrology; 3) Groundwater hydrology; 4) Biological indicators; and 5) Climate change (Mijangos Carro et al., 2017). Under the framework of ecohydrological integrity, Cueto-Espinosa (2019) conducted an analysis of integrity in the Zanatenco River Watershed, Chiapas. For this analysis, they introduced notions of watershed, integrity, and management to develop a systematic working structure. They incorporated various contributions related to the assessment and integration of variables and parameters related to ecosystem quality, biodiversity, landscape ecology, water quality, and others. Similarly, an ecological integrity study was conducted in the Jalpan River Microwatershed (Torres-Olvera, 2018) using various indices and evaluations.

Considering this technical and methodological diversity, as well as the limited sources of data and information to assess watershed integrity within the context of Mexico’s territory and the need to implement a tool that allows better analysis and management of the watersheds, the objective of this study was to develop a feasible way to implement the IWI under logistically challenging conditions, like a limited budget and small research team. The IWI was the selected option to evaluate the integrity of the watershed since it proposes a broad set of stressors, which are visible in the local circumstances. In addition to generating global results for the entire watershed, it allows observation of results on the conditions of the different functions of the watershed individually, which is important for specific and localized ecosystem management and remediation. In this case, we aimed for the implementation of the IWI to assess the integrity of LMW. This development offers enhanced possibilities for decision-makers in Mexico and other regions facing research gaps and limited budgets, allowing them to have a tool for generating information, monitoring, and better management of watershed-related activities.

MATERIALS AND METHODS

Description of the La Laborcilla Microwatershed

The LMW is located on the Central Mexican Plateau in the municipality of El Marqués, in Querétaro State; it extends partially to the northwest of the municipality of Colón in the same state and southeast of the municipality of San José Iturbide, in Guanajuato State (Figure 1). The LMW is an intramountain exoreic sixth-order microwatershed with a 70.51 km² area and altitudes ranging from 2,177 m to 3,287 m above sea level (asl). The drainage network is dendritic, originating in the slopes and foothills of the Pinal de Zamorano Volcano. It is the headwater of the Querétaro River Watershed, a subwatershed of the Lerma-Chapala-Santiago Watershed. The site constitutes the division between the Lerma Santiago (RH-12) and Pánuco (RH-26) hydrological regions. The local meteorology in the study area is as described for the nearby San Juan del Río Basin (Hernández-Pérez et al., 2022). Monthly relative air humidity ranges from 14% to 100%, typically exceeding 40% during the wet season (June-September). The monthly mean temperature ranges from 14 °C in winter (dry season) to 20 °C in summer (wet season), with an average of 17 °C. Annual precipitation varies from 400 to 850 mm/year, and potential evapotranspiration ranges from 500 to 800 mm/year (1971–2001; Carrera-Hernández et al., 2016). The yearly accumulated evaporation was recently determined using physical and isotopic methods, with values of 531.0 mm in 2016 and 768.6 mm in 2017 (Hernández-Pérez et al., 2020).

Figure 1.

Location map of the Laborcilla Microwatershed (LMW) in Central México Plateau. The LMW is located between Querétaro and Guanajuato states. The protected area and ejidos agricultural areas are located within the microwatershed. Urban areas and roads are shown as stressors.

The LMW is predominantly rural, mostly with wildland surfaces. Within the microwatershed extension, a population of 1,204 inhabitants is distributed in Los Trigos and La Laborcilla settlements, and farming areas are conformed by La Laborcilla, Los Trigos, and El Coyote ejidos (rural communally held areas; Registro Agrario Nacional, 2020). Part of the LMW territory is inside the “Dr. Mario Molina-Pasquel” Natural Protected Area (ANP) and the Priority Terrestrial Region RTP-100 “Cerro Zamorano” (Arriaga-Cabrera et al., 2000; SEDESU, 2003). El Cerro Zamorano is considered one of the country’s Important Bird Conservation Areas (AICA) and shelters 19 species with some level of protection (CONABIO, 2018; SMAOT, 2020). In addition to its significant hydrological functions at a regional scale, the microwatershed contains sections of oyamel forest (Gómez-Sánchez, 1997), gallery forest (Rzedowski, 2006) along specific streams, and the presence of three endemic vascular plants: Cirsium zamoranense, Rubus macvaugianus and Valeriana zamoranensis (Rzedowski, 2012). It also provides ecosystem services related to aquifer recharge and germplasm maintenance (Arriaga-Cabrera et al., 2000). There are 300 estimated species of fauna in the microwatershed, including some species that are subject to special protection and one threatened species under federal environmental protection regulations in the NOM-059-SEMARNAT-2010 (DOF, 2010)

In terms of environmental regulations and policies, the various biophysical and spatial components of LMW are subject to federal legislation like other microwatersheds and national territories. For example, the National Water Law (LAN; DOF, 2023b) states in Article 3, Section XLVII, that the federal zone should include ten-meter-wide protection strips adjacent to streams, and the utilization of these buffers requires concession permits granted by the National Water Commission (CONAGUA). On the other hand, the General Law of Ecological Equilibrium and Environmental Protection (LGEEPA; DOF, 2021) is the primary environmental law in Mexico, establishing a series of measures for environmental protection that can be applied at the local, regional, and national levels. These regulations and policies include soil conservation, pollution prevention, control and restoration of damaged ecosystems, biodiversity protection, and sustainable management of natural resources. The territory of the LMW is subject to the Local Ecological Planning Program (POEL) through Environmental Management Units (UGA) in the State of Querétaro, specifically for the municipalities of El Marqués (SEDESU, 2018a) and Colón (SEDESU, 2018b), where the designated land use policies are solely for protection and restoration. Additionally, the Sustainable Territory Planning Model of the State Program for Urban Development and Territorial Ecological Planning (PEDUOET) (IPLANEG, 2019) in Guanajuato considers a single land use for the northwest section of the microwatershed in the municipality of San José Iturbide, with the designation of protected. However, POEL and other similar instruments, such as Management Plans for ANPs, generally lack specific indicators to assess the proposed strategies in terms of integrity, protection, or evaluation of the watershed.

Despite the aforementioned biophysical characteristics and applicable regulations for the site, the specific environmental situation in LMW reflects local and national level inefficiency in environmental governance and governability in Mexico to improve or protect the integrity of watersheds. In many cases, there is a lack of coordination, conflicts of interest, centralized decision-making, and perspectives that prioritize the economic exploitation of ecosystems at the expense of environmental protection (Brenner and Vargas, 2010). Some of these deficiencies in the study site were made apparent through a supportive analysis that we conducted through semi-structured interviews with LMW stakeholders and authorities who have a perspective of the ecosystem functions from a utilitarian notion. With the situation in LMW, there are diverse regulatory absences regarding river ecosystems and water bodies and rigid and intermittent official intervention mechanisms. All of these factors hinder the conservation, management, and protection of the microwatershed.

Alongside the LMW, various regional locations have also been subjected to hydrological pressure on different ecosystem functions, exacerbating degradation processes. For example, in LMW and other contiguous microwatersheds during the Colonial period, forests were exploited and livestock introduced, which still has a strong presence as an economic activity in the area, along with land-intensive agricultural practices (Lira, 1990). The municipality of Colón, located within the Semidesert Forest Management Unit (UMAFOR), experienced deforestation of 1,000 hectares between 1993 and 2002 due to anthropogenic activities. This was the largest area of deforestation belonging to the same UMAFOR compared to the municipalities of Cadereyta, Ezequiel Montes, San Joaquín, and Tolimán (Musalem López et al., 2007). Similarly, during the same period, the municipality of El Marqués, belonging to the Lerma-Otomi Subwatershed UMAFOR, experienced a human-induced deforestation process of 767 hectares, being the municipality with the highest deforestation in this unit (Prieto-Martínez, 2007).

Evidence of pollution has been observed in the LMW primary stream, where solid waste and soapy water are present; infrastructure works also occur inside the area (González-Cadena, 2019) related to the urbanization of the localities. Through anticipatory observations, alterations of varying degrees have been identified in floodplains in different sectors. Regarding land degradation at the site, it is estimated that approximately 65.61% of the land area of the microwatershed is anthropically altered (Musalem López et al., 2007).

Watershed integrity assessment methodologic approach

As we described before, this analysis is based on the IWI (Flotemersch et al., 2015), which was developed with the intention of providing an index that comprehensively assesses six key measurable functions that are essential for understanding the condition of a watershed: A) Hydrological Regulation (HYD); B) Water Chemical Regulation (CHEM); C) Sediment Regulation (SED); D) Hydrologic Connectivity (CONN); E) Temperature Regulation (TEMP); and F) Habitat Provision (HABT). These functions are integrated into a single index on a scale of 0 to 1, calculated as the product of the six key measurable functions. The above-mentioned suggests that the complete loss of any of the six functions would result in a value of 0 (indicating the complete loss of watershed integrity). IWI has been applied to the contiguous United States territory (Thornbrugh et al., 2018), the Matanuska-Sustina watershed in Alaska, and four watersheds in the Balkan Peninsula (Aho, Flotemersch, Leibowitz, Johnson, et al. 2020; Aho, Flotemersch, Leibowitz, Lacroix, et al. 2020).

The developers of the ICI and IWI acknowledged the difficulty of finding reference sites in pristine conditions and that it is not appropriate to select sites from other regions that could represent a hypothetical reference state. Due to these circumstances related to anthropogenic landscape alteration, the ICI development is based on risk factors for key functions occurring within the watershed. Because of the lack of datasets and equivalent environmental information for all the parameters used to initially develop the IWI, and considering the scale of the LMW study site, we developed a group of additional indicators to represent and enable the evaluation of these functional components which preserve coherence with the original IWI concept.

To compensate for the lack of information and data mentioned and to be able to carry out a reliable assessment, we used indicators of three levels of intensity for obtaining and compiling data (Brooks et al., 2003; Tiner, 2004; Unnasch et al., 2008; USEPA, 2006).

1. Remote level: Obtained through cartographic information and field calibration with resources focused on extensive spatial scales and obtained through remote sensing and GIS.

2. Rapid level: Obtained by the integration of remote sensing information and qualitative field assessments, such as visual evaluation methods.

3. Intensive level: Obtained by quantitative field measurements and sampling designed under appropriate statistical methods.

Complementary indicators of hydrogeomorphological conditions and water physiochemistry were generated using the Environmental Water Quality Index (EWQ(i)) and the Hydrogeomorphological Index (IHG) (Ollero-Ojeda et al., 2011) and integrated into the assessment.

Delimitation of hydrological network and Catchment Units (CU)

A watershed is a spatially delimited area defined by topographical heights or headwaters; within this area, runoff streams concentrate at an outlet point in the lowest topographical areas. Catchments are defined as nested areas within the watershed. Hydrological flow within the main channel of a catchment is locally generated throughout the catchment and through import accumulated from upstream catchments – except in the case of headwater catchments, where all runoff is generated locally. Both indices represent the integrity of six ecosystem functions at multiple scales and integrate different stressors that affect one or multiple functions. However, the IWI is a cumulative index that aggregates upstream conditions and represents watershed-scale processes, while the ICI describes local integrity that is independent of upstream conditions (Johnson et al., 2019).

Although manual vectorization is more labor-intensive than automated methods, it was necessary in this case because the scale of the work is a microwatershed requiring detailed analysis, and the available 15-meter DEM from the Mexican Elevation Continuum (CEM) 3.0 by the National Institute of Statistics and Geography (INEGI, 2021) does not capture sufficient topographic detail.

To manually delineate the hydrological network, we used QGIS 3.16.11 (QGIS Development Team 2023) along with two referential data sources: hydrographic network and topographic chart contained in Series III of Vector Sets of Topographic Information dataset from the National Institute of Geography and Informatics (INEGI, 2015) and a raster generated through an automated process using the SAGA module Channel Network and Drainage Basins (Conrad et al., 2015) with the aforementioned DEM.

To delineate Catchment Units (CU), the Strahler method ((Strahler 1957), as described in the Multi-Scale Assessment of Watershed Integrity (MAWI; Lin et al., 2008) was used. As there are no datasets available containing these specific hydrographic areas, we used the previously generated raster data and adapted the mentioned methodology delineating the CU with the following criteria:

1. In the downstream direction, a boundary point was established for the CU from the origin of a first-order stream to the intersection where the second-order stream of the proposed CU merges with another second-order stream.

2. In the downstream direction, two additional boundaries were established for the CU delineation: I) At the convergence with other second-order or larger streams and II) Where relevant geological, geomorphic, or topographical boundaries were observed.

Specific CUs are named based on their orientation; for example, CU-SW is the name of the CU located at the southwest of the microwatershed.

Hydrogeomorphological Index (IHG)

We used the parameters shown in Table 2 for the development of the Hydrogeomorphological Index (IHG) and integrated them into the proposed index as indicators of the Remote and Rapid level categories. The integration of these additional indicators is appropriate to assess the anthropogenic impacts that disrupt the functionality of the fluvial system. While it is important to gather information to observe reference conditions of these systems, the IHG remains flexible, recognizing that access to such information is often challenging, and it can be used partially and adapted to different criteria and objectives (Ollero-Ojeda et al., 2007).

Table 2.-.

Parameters used to calculate the Hydrogeomorphological Index (IHG)

Parameter	Description
Flow regime naturalness	This parameter is assessed in relation to the natural state. This standard of comparison implies that the river currently has a natural discharge regime with seasonal flow changes and floods.
Sediment supply and mobility	This parameter is assessed by examining how dams, dredging and extractions alter and reduce sediment flows. Importance is also given to the lateral inputs of sediment through mass failure processes and the contribution of tributaries.
Floodplain functionality	This parameter is assessed by considering how the presence of human activities in a floodplain could seriously modify its functionality.
Channel morphology and planform naturalness	Changes in the channel planform are evaluated by considering whether they are direct (channel realignment) or indirect (regulation, deforestation) human alterations.
Riverbed continuity and naturalness of the longitudinal and vertical processes	This parameter is estimated by considering the impact from dams and weirs (barrier effect, breaking longitudinal continuity, triggering incision processes downstream), and also from other types of human alterations in channels (dredging, gravel extractions, floorings, and vegetation clearcutting).
Riverbank naturalness and lateral mobility	This parameter considers pressures that confine the lateral mobility of the channel or alter the erosion and sedimentation processes (especially bank defences).
Longitudinal continuity (riparian corridor)	This parameter is assessed according to the number of dis continuities in the riparian corridor resulting from human occupancy.
Riparian corridor width	The current width is assessed relative to the optimal width in the past or in a reference scenario.
Structure, naturalness and cross-sectional connectivity of the riparian corridor	Riparian patches and the internal quality of the riparian zone are estimated by evaluating disturbances and ruptures in the connectivity of the corridor.

The updated version of the IHG considers various functions of hydrogeomorphological dynamics in fluvial system; this allowed us to assess key river functionalities important to the watershed integrity (like channel and riparian quality or sediment supply and mobility) and allows for the direct identification of anthropogenic impacts or alterations of different types and magnitudes that modify the system functionality (Ollero-Ojeda et al., 2011). The evaluation of the IHG requires the assessment of remote sensing images, mapping, and fieldwork based on proposed observations and measurements. In the case of anthropogenic alterations to the natural functions of the river system, the methodology applies penalties that affect the final expected value of the key functions. The maximum score for the key function is ten (10) points for each of the nine (9) parameters, resulting in a maximum score of ninety (90) points for an optimally functioning river system. In this case study, certain measurements, such as granulometry and topographic surveys, were excluded. Instead, the use of GIS and the qualitative observations proposed in the IHG were conducted.

The delineation of the functional sectors of the fluvial ecosystem with a length of 1 km was established, taking into account the suggested length in the IHG methodology (Ollero-Ojeda et al., 2009). For the LMW, it is feasible to divide the streams into regular lengths rather than using hydrogeomorphological criteria, as indicated in the IHG. Subsequently, we conducted an in-situ survey along the primary stream of the microwatershed, covering the total length of the reaches generated earlier with an approximate length of 1 km each. Stream sections that could not be directly evaluated due to their location or physical characteristics were evaluated through indirect sources such as aerial photographs, documents, and other sources of information, as suggested in the IHG.

Environmental Water Quality Index EWQ(i)

We developed an Environmental Water Quality Index (EWQ(i)) to integrate the water physicochemical data, to accurately calculate the IWI, and to integrate the information to assess the relative conditions of the Chemical Regulation component of surface water. The development of this index involved ten physicochemical parameters (Table 3).

Table 3.-.

Indicators and weights of parameters used to calculate the Environmental Water Quality Index EWQ(i)

Parameter	Indicator	Weight (Px)
Acidity	mg/l CaCO3	1
Hardness	mg/l	2
Dissolved oxygen	mg/l O2	5
Nitrates	mg/l NO3- -N	2
Phosphates	mg/l PO₄³⁻	3
Total dissolved solids	mg/l	3
Electric conductivity	µS/cm	3
Dissolved carbon dioxide	mg/l CO2	2
Water temperature	°C
pH	Units of pH

The sample size for the evaluation was determined using the Sample Size Table tool published by The Research Advisors® (2006), which uses the following equation (Krejcie and Morgan, 1970):

$$n=\frac{x^2·N·P\left(1-P\right)}{\left[{ME}^2\left(N-1\right)\right]+\left[x^2·P\left(1-P\right)\right]}$$ (1)

where $n$ represents the number of points where water samples for chemical analysis were collected. To calculate $n$, we considered the standardized values of chi-square ($x^2$) for the specified confidence level with 1 degree of freedom, a 15% margin of error (ME²), an 80% confidence interval, and a population proportion of P=0.50. The total population was N=18 and represents the total length of the primary stream (18 km). For this case, the number of sites to be sampled was nine (n=9), and the sampling sites were distributed along the main stream according to the following criteria:

1. Points that accumulate the inflow of main streams from different CU.

2. Points that, in addition to considering the first criterion, take into account settlements, discharge points, and other anthropogenic factors that may directly induce changes in the physicochemical properties of the water.

3. Points separated by a distance ranging from a minimum of one kilometer to a maximum of two kilometers.

The desired product for CHEM is integrated by the results obtained from the analysis of the physicochemical parameters of water at the designated sites and are obtained by the following four stages:

1. A linear interpolation using values obtained from the on-site analysis as a reference to obtain values for the missing sites.

2. A logarithmic transformation for compressing the obtained data to avoid asymmetries from extreme values.

3. A weighting of the parameters was implemented, with reference to the analysis by (Rubio-Arias et al., 2014), due to the relevance of specific parameters related to water quality in relation to the maintenance of various ecosystem processes.

4. After interpolating the missing values, transforming them into a logarithmic scale, and weighting them based on their relevance, the parameters were arithmetically aggregated using the following equation:

   $$Q=\frac{T{\left[\begin{array}{c}{A}_c\left(P_{Ac}\right)+{CO}_2\left(P_{{CO}_2}\right)+O_2\left(P_{O_2}\right)+D\left(P_D\right)+\\ {NO}_3^{-}\left(P_{{NO}_3^{-}}\right)+{PO}_4^{3-}\left(P_{{PO}_4^{3-}}\right)\\ +SDT\left(P_{STD}\right)+\sigma \left(P_{\sigma }\right)\end{array}\right]}^{\left(\frac{pH}{10}\right)}}{20}$$ (2)

   where $Q$ is the EWQ(i); $T$ is water temperature (°C); $Ac$ is acidity; ${CO}_2$ is dissolved carbon dioxide; $O_2$ is dissolved oxygen; $D$ is hardness; ${NO}_{3^{-}}$ is nitrate; ${{PO}_4}^{-3}$ is phosphate; $SDT$ is Total Dissolved Solids; $\sigma$ is electrical conductivity (µS/cm); $pH$ is pH value; and $Px$ is the weight for each parameter. All constituents were log normalized, except for temperature and $pH$, and units for all constituents were expressed in mg/L except for $pH$ and where otherwise noted.

The dissolved oxygen (${\mathrm{O}}_2$) parameter was transformed to negative in the EWQ(i) to enhance the index’s coherence and accurately reflect its impact. Although higher ${\mathrm{O}}_2$ levels generally indicated better water quality, adjusting the sign made lower ${\mathrm{O}}_2$ values have a more significant adverse effect on water quality.

This equation can be considered empirical in nature (Whittembury G. and J. Whittembury, 1957); it was developed with reference to certain elements in the mathematical aggregation proposed for the Simplified Water Quality Index (ISQA; Queralt, 1982).

The following considerations were also taken into account. Temperature not only impacts biological activity but also the chemical activity of the water, as temperature is a determining factor in the energy supply to the lotic system. Therefore, the temperature value was positioned as a coefficient that multiplies the set of analyzed variables (similar to ISQA) in the utilized equation (Glasstone, 1979).

The pH value is arranged as an exponent in the equation since any changes in pH have a significant, exponential impact on water quality. The mathematical argument is based on the fact that dividing the pH value by ten results in figures close to one, yielding numerical values compatible with the previously applied scale. At the same time, the calculation becomes more sensitive to minute changes in pH when using up to two decimal places. Finally, the Common Divisor Factor (CDF) with a value of 20 was determined by two criteria: 1) The standard temperature, which is 20°C and is established by the National Institute of Standards and Technology (NIST; Doiron, 2007); 2) 20°C corresponds to the temperature data extracted from the Climatological Normals 1981–2000 of the National Meteorological System (SMN; CONAGUA 2009). These data were grouped quarterly, averaged, and mathematically rounded to whole numbers to obtain the CDF (Table 4).

Table 4.-.

Common Divisor Factor based on the temperatures of the Climatological Normals

Sampling Months	General temperature	Precipitation	Common Divisor Factor
December-February	Cold	No rain	15
March-May	Warm	No rain	20
June-August	Warm	Rain	21
September-November	Tempered	Partial rains	18

Index of Catchment Integrity (ICI) and Watershed Integrity (IWI)

To assess the integrity of the LMW, we followed the IWI methodological framework (Flotemersch et al., 2015). A matrix of stressors that affect the integrity of the microwatershed was developed. These stressors were defined in two categories: within the stream channel and outside the stream channel (Table 5). Subsequently, stressors were associated with each of the six functional components that they are related to (Table 6).

Table 5.-.

Microwatershed stressors within the stream channel and outside the stream channel

Stressor	Name
Outside the Stream Channel
Agriculture (Non-riparian; milpas (traditional crop-growing system), plows, some tractors) (% of area)	AgrTer
Disturbed Forest (Non-riparian; thinning due to timber, cattle grazing) (% of area)	BosPe
Loss of forests to grasslands (% area)	BosPa
Urban land use (Low density, some concrete streets and bridges, concrete houses, warehouses) (% of area)	UrbTer
Low permeability surfaces of anthropic origin (related to human settlements and historical logging) (% of area)	ImpTer
Riparian Disposal (Crops, Timber, Livestock; IHG Assessment)	RibAlt
Road Density (concrete roads, trails, sidewalks; km/km2)	CamDens
Floodplain Alterations (Streets/Bridges, Urban Land Use; IHG Assessment)	LLainAlt
Within the Stream Channel
Longitudinal Stream Defenses (Stone Walls; IHG Assessment)	DefLon
Sediment Incrustation (Bedrock Embedding in Fine Sediment; IHG Assessment)	IncSed
Simplification or alteration of the natural shape of the channel or reduction of sinuosity (IHG Assessment)	CanAlt
Topological alterations of the channel (Excavations in the channel for human and cattle access to the water, alterations of the vertical morphology, obstacles that alter the longitudinal continuity; IHG Assessment)	TopoAlt
Changes in water quality (diffuse pollution from livestock activities, agriculture, urban discharges and impermeable surface; EWQ(i) Assessment)	AgAlt
Road/stream intersections (Greater presence in lower order streams; intersections/km2)	CarInt

Table 6.-.

Functional components related to the stressors

Functional Component	HYD	CHEM	SED	CONN	TEMP	HABT
Stressor
AgrTer	X	X	X		X	X
BosPe	X		X
BosPa	X		X
UrbTer	X	X	X		X
ImpTer	X	X	X
RibAlt	X	X	X	X	X	X
CamDens	X
LLainAlt	X			X
DefLon	X	X	X	X
IncSed			X
CanAlt	X			X
TopoAlt	X			X
AgAlt		X
CarInt				X		X

To generate this matrix, stressor information equivalent to those used in the original index was used; however, stressor indicators from the IHG and EWQ(i) substituted some of these elements, and others were omitted altogether. The following criteria were used for substitution or omission: 1) Stressors that lack available data or relevant information for the study site and 2) Stressors that were not suitable for the project spatial scale framework and site-specific characteristics. Any absent stressors were replaced by stressors that were observed and evaluated in situ. The data dictionary included: 1) Catchment Units (CU); 2) Stressors; 3) Values from the EWQ(i); 4) Values resulting from in situ evaluation of IHG parameters; and 5) Values for the suggested stressors for the original IWI calculation in each CU, such as the density of road and channel intersections or the percentage of specific land cover types.

To calculate these IWI indicated stressors, vegetation and land cover types were classified using a combination of vector data and manual supervised digitization techniques. The Vector Sets of Land Use and Vegetation. Scale 1:250,000. Series VI (Union Layer) from the National Institute of Statistics and Geography (INEGI, 2016) served as the base dataset, which was corrected and adjusted to match the scale of the microwatershed area. Sentinel-2B images from the near-infrared (NIR) band acquired from Copernicus Open Access Hub were used throughout the process to provide detailed information for the digitization. Manual and visual digitization of vegetation types and land cover was performed using QGIS 3.16.11. (QGIS Development Team 2023) To ensure the accuracy of the classification, field verification of sampling points was conducted. For road density and road intersection stressors, the information was extracted from Series III of Vector Sets of Topographic Information dataset from the National Institute of Geography and Informatics (INEGI, 2015).

Subsequently, the maximum value for each stressor was identified. For proportion-based stressors, the maximum value was 100 (e.g., percent of forest area lost to grasslands), while for stressors extracted from the IHG, the maximum value was 1. In cases where stressors did not have a theoretical maximum value, the maximum value found across the CU’s was used. The stressor values are then transformed into a scale ranging from 0 (minimal impact) to 1 (maximum impact). Due to the small number of CUs, to avoid extreme values ​​in the calculation and approximate the results to the actual site conditions, data from a seventh CU were integrated for stressors without a theoretical maximum value (e.g., road/stream intersections). This CU was located outside of the LMW but within the Queretaro River watershed, inside ZMQ, a zone with higher anthropogenic pressure. The ICI was then calculated for each component based on the following:

$${\widehat{ICI}}_{i,c}=\frac{{\sum }_{j=1}^{n_{i,c}}\left[1-\left(\frac{s_{j,c}}{s_{j,cmax}}\right)\right]}{n_{i,c}}$$ (3)

where ${\widehat{ICI}}_{i,c}$ is the first order ICI estimator of the ith functional component for catchment $c,s_{j,c}$, is the value for the jth stressor in catchment $c,s_{j,cmax}$, is the maximum (highest possible level of degradation) value for the jth stressor across all catchments, and $n_{i,c}$ is the number of stressors associated with the ith functional component in catchment c. The stressor is divided by the maximum possible stressor value to standardize stressor values, so that $\left(\frac{s_{j,c}}{s_{j,cmax}}\right)$ vary from 0 (absence of stressor) to 1 (maximum stressor value) (Aho, Flotemersch, Leibowitz, Johnson, et al. 2020)

Our analysis uses two distinct measures of watershed integrity. The first one is the IWI as described by Flotemersch et al., (2015), analyzed by Thornbrugh et al., (2018) and modified by Aho, Flotemersch, Leibowitz, Johnson, et al. (2020). Briefly, this approach first calculates the six watershed functions (hydrologic regulation, regulation of water chemistry, sediment regulation, hydrologic connectivity, temperature regulation, and habitat provision) that are essential to support, maintain, and sustain the full range of ecological processes and functions within a watershed. Each of the functionary components are calculated by averaging the normalized values of one or more stressors over all watersheds as follows:

$${\widehat{IWI}}_{i,w}=\frac{{\sum }_{j=1}^{n_{i,w}}\left[1-\left(\frac{s_{j,w}}{s_{j,cmax}}\right)\right]}{n_{i,w}}$$ (4)

where ${\widehat{IWI}}_{i,w}$ is the estimate for subindex $i$ and watershed $w,s_{j,w}$, is the value for the jth stressor associated within watershed $w,s_{j,cmax}$ is the maximum value (peak value of impact) for the jth stressor across all catchments, and $n_{i,w}$ is the number of stressors associated with subindex $i$ in watershed $w$. In this equation, the stressors were normalized by maximum catchment values, rather than maximum watershed values. This was necessary in order to properly scale the watershed and catchment indices (Aho, Flotemersch, Leibowitz, Johnson, et al. 2020; Johnson et al. 2019). Note that a particular stressor, such as agricultural land use, can appear in more than one subindex since it can act upon different watershed functions in distinct ways. The IWI is then calculated as the product of these six subindices:

$${\widehat{IWI}}_w={\prod }_{i=1}^6{\widehat{IWI}}_{i,w}={\prod }_{i=1}^6\left(\frac{{\sum }_{j=1}^{n_{i,w}}\left[1-\left(\frac{s_{j,w}}{s_{j,cmax}}\right)\right]}{n_{i,w}}\right)$$ (5)

where ${\widehat{IWI}}_w$ represents the overall integrity of the watershed scaled between 0 and 1 (with higher values indicating greater integrity), calculated as the product of the six subindices (i.e., functional components; Aho, Flotemersch, Leibowitz, Johnson, et al. 2020; Aho, Flotemersch, Leibowitz, Lacroix, et al. 2020; Flotemersch et al. 2015) and the other values are defined as above.

The second approach is a simplification of the IWI defined as Simplified Integrity Index (SII). In this case, we calculate the index directly from the watershed stressors, without including the intermediate step of calculating functional complement subindices. This was done using the following equation:

$${\widehat{SII}}_w=\frac{{\sum }_{j=1}^{n_w}\left[1-\left(\frac{s_{j,w}}{s_{j,cmax}}\right)\right]}{n_w}$$ (6)

where ${\widehat{SII}}_w$ is the index estimate for watershed $w$ and the other values are defined as above. These two approaches for measuring watershed integrity were similarly applied to estimate catchment integrity, but substituting catchment stressor values ($s_{j,c}$) and number of catchment stressors ($n_c$).

Decision-maker interviews

To analyze the decision-making processes developed by the stakeholders regarding LMW and its integrity status, semi-structured interviews were carried out. Through a dialogic conversation perspective aimed at achieving closer proximity and trust to facilitate a reflective process and an interpersonal exercise between the subjectivity of the interviewee and the interviewer, the semi-structured interviews were conducted using an auxiliary 20-question survey merely as a reference. The goal was to develop a consensual and negotiated view of the facts in order to give a greater sense of truthfulness to what is expressed (Russell and Kelly, 2002) and to conduct an analysis of “what is said to be done” (Bruner, 2006) to observe correspondences in moral and ideological stances, as well as normative aspects, interests, and other features related to the topic.

The interviews were conducted with three mid-level and high-level public officials from the three levels of government (municipal, statal, federal) of public agencies with participation in the Queretaro River Watershed Commission; those agencies are responsible for regulation, planning, and care in water, environmental, and sustainable development issues, and three local authorities (President of Ejidal Commissariat, Community Subdelegate, and Head of the Protected Natural Area) to understand how they address the following issues from their respective administrative and jurisdictional domains using three categories: 1) Information used to support decision-making regarding the biophysical integrity of the watershed (IDM); 2) How the watershed perspective and watershed integrity are integrated into environmental public policy instruments (WIP); and 3) Which formal collaboration arrangements exist for decision-making and intersectoral work regarding the care of the watershed (FCW).

The interview sessions were conducted with the participation of two observers (Alder and Adler, 1994) to provide greater validity and reliability. They were implemented taking into account the sociocultural context of the interviewees, seeking concordance in the referential, linguistic, and symbolic frameworks of the exercise in relation to the researcher, the study, and the subjects of the study (Taylor and Bogdan, 1987). Observational notes and theoretical notes (Schatzman and Strauss, 1973) were generated to properly organize the information collected. Finally, the interview content was analyzed using a deductive approach (Goetz and LeCompte, 1988), focusing on the three mentioned categories. The identities of the interviewees were handled anonymously.

RESULTS

Catchment Integrity

When considering the interaction of stressors between individual functional components for the calculation of the ICI (Figure 2), differences were seen for individual key function subindices, and values higher than 0.8 were generally obtained. However, two exceptions with lower results were observed with CHEM in the CU-SW (0.71) and CU-S (0.79). This situation arose due to the EWQ(i) results, in conjunction with the presence of human settlements and the proportion of agricultural areas. Likewise, a third exception occurred in HABT in the CU-N (0.73) due to the high number of intersections between roads and streams. Finally, a fourth exception occurred with the TEMP functional component in the CU-SW (0.77) in relation to the devegetation of land surfaces but also due to the deterioration of riparian vegetation. This latter CU had the lowest degree of integrity (ICI=0.27), whereas the CU-NW had the highest integrity (ICI=0.58). The results for the individual functional components of the ICI indicate that all the CUs, except CU-NW, had integrity values below 0.50 (Figure 3).

Figure 2.

Map of the Index of Catchment Integrity (ICI) and Index of Watershed Integrity (IWI) for the LMW. a) shows results from ICI, which describes local integrity of CUs. b) shows results from IWI, which comprise aggregation of upstream impacts.

Figure 3.

ICI and subindices for each functional component. The ICI is obtained by the product of the components using Eq. 3 where catchment stressor values ($s_{j,c}$) and number of catchment stressors ($n_c$) are substituted for the watershed variables. The highest ICI value is observed in the CU-NW while the lowest ICI value is observed in the CU-SW.

Watershed Integrity

The spatially aggregated IWI values for the six nested CUs in this microwatershed do not vary from ICI results except in the CU-S (IWI=0.45) (Figure 2). The complete LMW results indicated medium levels of integrity (IWI=0.43) (Figure 4).

Figure 4.

IWI and subindices for each functional component. The IWI is obtained by the product of the components using Eq. 5. The highest IWI value is observed in the CU-NW while the lowest IWI value is observed in the CU-SW. However CU-S value slightly differs from ICI results. In addition, overall LMW IWI value is showed.

Simplified Integrity

For the SII, all the CUs, except the CU-SW (SII=0.78), had values above 0.8 (Figure 5), indicating that using the non-aggregated approach resulted in a high degree of integrity. The CU-SW, even without considering upstream effects, already presents a lower degree of integrity than other CUs, which is an indication of its more deteriorated condition (Figure 6).

Figure 5.

Map of the Simplified Integrity Index (SII) for the LMW. The results show the condition of integrity without considering the aggregation of upstream impacts.

Figure 6.

SII for each CU. Instead of taking into account the six individual functional components of the watershed, the index was calculated directly from stressors using Eq. 6. The six microwatershed’s CUs show SII values between 0.78 to 0.87. CU-SW still shows the higher degradation value.

Decision-maker interviews analysis

The analysis sought to scrutinize the interviews conducted with the Head of the Protected Natural Area (ANP), the Community Subdelegate, and the President of the Ejidal Commissariat, alongside contributions from officials across the three levels of government regarding governance issues of La Laborcilla microwatershed. Considering the three categories used for the analysis: 1) Information used to support decision-making regarding the biophysical integrity of the watershed (IDM); 2) How the watershed perspective and watershed integrity are integrated into environmental public policy instruments (WIP); and 3). Which formal collaboration arrangements exist for decision-making and intersectoral work regarding the care of the watershed (FCW).

For the IDM category, interviewed actors exhibit varying levels of knowledge and perspectives directly impacting decision-making about the watershed’s integrity. The ANP Head relies on the Secretariat of Sustainable Development (SEDESU) and the Secretariat of Agricultural Development (SEDEA) to carry out their duties and possesses practical knowledge about forest management and biodiversity. However, these duties lack a deep technical understanding of hydrodynamics and watershed functioning and do not have the technical or logistical capacity to mitigate environmental impacts from improper environmental practices (like illegal logging) performed by community or external agents. This knowledge gap limits their ability to make informed decisions for managing the watershed within the ANP. Meanwhile, the Community Subdelegate from La Laborcilla, an auxiliary authority of the municipality, employs an empirical ecosystem management approach based on traditional experiences, which is useful in various scenarios but also faces significant difficulties in effective management, revealing a disconnection between local experience and more technical strategies.

On the other hand, the President of Ejidal Commissariat, the organization responsible for executing assembly agreements and representing and managing the ejido (Agrarian Law; DOF, 2023a), also lacks technical knowledge but has a common-sense approach oriented towards protecting the ejido and indirectly certain natural areas of the site due to a sense of belonging and idiosyncrasy. However, he displays strong distrust towards government interventions, a stance based on past experiences of poorly managed or failed government projects and perceptions of threats to local autonomy, as well as a lack of knowledge about the impact of livestock activities carried out on the site.

At the municipal level, the high official from the Secretariat of Sustainable Development of the Municipality of Colón reveals a general lack of awareness of the legal and ecological situation of the micro-watershed, and the omission of authorities leads to impunity in invasions of federal zones and alterations of riparian zones. This indicates that the lack of shared information and a clear strategy weakens the capacity to respond to watershed challenges. At the state level, the interviewee, assigned to the Directorate of Environmental Planning of SEDESU, mentions the need to strengthen the dissemination of information on watershed-related topics to the general population to enhance governance processes.

At the federal level, an official from the Sub-Directorate of Watershed Councils, Social Management, and Emergency Attention of the Local Directorate of the National Water Commission (CONAGUA) highlights challenges in enforcing laws to protect the federal zone, with predominantly administrative procedures that rarely escalate to more significant legal actions. There is a mention of the need for regularization and consultation for the use of the federal zone. In this case, the information used is more of a regulatory type, and decision-making is noted to be more reactive than proactive.

Regarding the WIP category, the information provided by government officials indicates a significant disconnection between the intention to carry out specific projects (possibly with significant environmental impacts) and the environmental regulations that should protect the watershed. At the municipal level, political practice appears to focus more on resolving emerging conflicts rather than integrating a comprehensive management vision of the watershed. At the state level, it is acknowledged that public policy instruments such as POEL or Management Plans for ANPs are not synchronized with an effective watershed approach, commenting that although land uses, policies, criteria, and Environmental Management Units (UGAS) are defined (SEDESU, 2018b), there is a lack of integration of the operational watershed approach in decision-making, which limits the effectiveness of public policies, but the potential of the IWI as a tool to define land uses for more precise watershed management strategies is recognized.

At the federal level, the limitation to administrative procedures in complaint management and the lack of specific regulations for natural areas outside federal jurisdiction (such as riparian corridors) reveal a gap that compromises adequate protection and management of such sites. The ANP Head argues that the lack of collaborative and formal planning suggests an insufficient integration of the watershed approach in managing the ANP. In terms of the Subdelegation, difficulties in generating consensus for effective environmental management are mentioned, reflecting a lack of coordination between government levels and community sectors, also mentioning disagreements within the community, and a sense of illegitimacy in the election of auxiliary authorities. On the other hand, the President of the Ejidal Commissariat expresses resistance to new environmental public policy instruments related to the watershed and protected areas, perceived as limitations to local freedom and potential land dispossession.

In the FCW category, it was observed that although collaboration among these key actors is crucial, it is severely limited by distrust and a lack of effective dialogue. This hinders the management of the watershed. Firstly, there is not a proactive recognition or mention of the Queretaro River Watershed Commission or watershed committee (microwatershed scale forum), which are the official participatory and water representation user forums (LAN; DOF, 2023b) in this case. Within the municipal context, the information points to a significant lack of formal collaboration, where dialogues seldom lead to continuity or tangible outcomes. Additionally, there is a noted need to build consensus to prevent adverse effects on the rights of the population while protecting the environment. At the state level, the need to improve dissemination processes and include various population sectors in watershed governance is recognized. At the federal level, collaboration tends to focus on managing complaints and regulations, although some opportunities for regularization and preventive consultations for activities in the federal zone are presented. Meanwhile, the ANP Head reports that current collaborations are limited and exclusive, significantly restricting community participation and effective management. The Community Subdelegate, despite being an official auxiliary authority, faces a notable lack of support and distrust towards government entities, reflecting ineffective and uncoordinated collaboration. Finally, the President of the Ejidal Commissariat shows distrust towards government institutions and resistance to commitments perceived as invasive or harmful.

DISCUSSION

Perspectives on the IWI assessment and possible improvements

Our study aimed to generate an objective approximation of the integrity conditions of the LMW, taking into account the theoretical approach, procedures, indicators, and equations suggested for the IWI (Flotemersch et al., 2015). We also incorporated other indicators and indices related to ecosystem conditions of the watershed to adapt the IWI to the scale of our study and the information that was available. In this microwatershed, different degradation interacting processes that compromise its functions were observed. The watershed is located in a predominantly rural area with some wild areas, where the population density, as well as the number of roads and infrastructure, is less than other microwatersheds inside the Querétaro River watershed. However, the LMW has also been subjected to processes of historical degradation over a period of hundreds of years. It is not only possible to observe the consequences of the cumulative effects in terms of interactions of stressors, but also the historic factors that continue to accumulate negative impacts. Regarding the stressors used in performing the ICI and IWI calculations, some affect not only the individual functional components but also multiple components simultaneously. In particular, one of the stressors (loss and alteration of riparian area) generates impacts on all the functional components. This ecosystem is one of the most altered among other types of ecosystems by anthropogenic impacts and is far from the natural condition (Kutschker et al., 2009). At the national scale, high levels of watershed degradation have affected the ecosystems and the well-being of the human population (Meli et al., 2017). Agricultural activities, urban surfaces, and longitudinal defenses like riprap walls in riverbanks impact four of the functional components. While such stressors do not cover large areas, they generate multiple impacts and are important to the integrity conditions of LMW.

The alternative approach of the SII has a dual purpose: first, it allows for a rapid and less complex assessment than ICI/IWI. Although it has less sensitivity due to its way of mathematically integrating stressors (without integrating the six key functions), compared to the original assessment, it can serve as an initial approach that, for example, allows the visualization of the integrity between CUs. On the other hand, it allows us to highlight the importance of considering the ecological interactions among key functions of the watershed in the original IWI approach, which considers that stressors can affect several functions simultaneously, generating cumulative impacts that cause a greater decrease in the integrity of the watershed compared to the SII which considers the general impact of stressors in the entire watershed.

The IWI requires adequate information on some of the conditions of the water network. However, there are nationwide gaps and omissions of data on the monitoring of the condition of the streams and riparian zones; this is true to an even greater extent in lower-order streams. Therefore, parameters of the IHG (Ollero-Ojeda et al., 2011) and the EWQ(i) in both their individual and assessment integrated forms function as appropriate stressors for the IWI since they are relevant environmental quality indicators related to human activities.

When comparing the IWI methodology implemented in our study with other watershed integrity assessments at the national scale, the following is observed. Firstly, the study carried out by SEMARNAT and IMTA (Mijangos Carro et al., 2017) considered factors related to surface hydrology, groundwater hydrology, biological indicators, and climate change. Each environmental component was evaluated individually and not integrated into an index or subindices related to functional components. Also, a perspective of individual components, cumulative impacts, or the relational interweaving between stressors and human activity was omitted. Secondly, in the analyses of ecohydrological integrity for the Zanatenco River Watershed in Chiapas (Cueto-Espinosa, 2019) and ecological integrity of the Jalpan River microwatershed (Torres-Olvera, 2018), spatial subdivisions of the study sites were considered, and classified as “conservation objects” or stream sections, both consider the watershed functional zones. Likewise, the influence of terrestrial surfaces status on the watershed integrity was considered and linked to threats and impacts derived from human activities. Therefore, this study bears similarities with the previously cited, but it does not contain a functional complement perspective.

The IWI as an Instrument of Environmental Governance

The concepts and indices related to watershed integrity have the potential to make a paradigm change in Mexican public policies related to watershed management. The IWI and ICI provide critical data on the biophysical status of watersheds. These assessments enable decision-makers to identify watersheds and CUs that are critically impaired or have low integrity and that should be prioritized for management and restoration (Thornbrugh et al., 2018). Conversely, they also identify high-integrity CUs and microwatersheds that must be protected. By evaluating the impacts of stressors on watershed functions, these assessments offer strategic, multi-scalar information essential for effective decision-making within a suitable governance framework. This approach also provides a broader conception of human impacts in watersheds in order to operate the best management practices and transition to better governance mechanisms.

Considering that human-induced stressors compromise the catchment integrity, we expect that their impacts would affect a broader hierarchical watershed units (Chaffin and Scown 2017, as cited in Aho, Flotemersch, Leibowitz, Johnson, et al. 2020). Also, a nested hierarchy perspective suggests that within a watershed framework, the functioning of larger river systems exerts influence on smaller-scale processes (Frissell et al., 1986). This insight remarks the necessity for specific policies for local and regional watershed management challenges.

At the local management scale (LMW), communities and ejidos are required to recognize the Catchment Unit (CU) as a minimum local governance unit that allows them to create managing solutions using the ICI lower-level data. This low-level data is directly related to stressors, and it is useful for communities to observe the impacts of their activities on the CU components to fulfill their traditional management practices with the watershed functioning comprehension. Integration of such knowledge can lead to more informed decision-making (Hirokawa, 2012) regarding water and land management, facilitating ecosystem services conservation and society resilience (Pereira-Guimarães, 2011). At LMW, stressors like riparian removal, road-stream intersections, or disturbances in terrestrial ecosystems linked to agricultural activities are indicators of the necessity to conduct a productive transition towards a decrease of forest resources exploitation and agricultural practices such as agroecological systems and regenerative cattle ranching, better management of road infrastructure and better riparian zone management. These practices not only reduce stress factors to the streams and the catchment unit but can improve local productivity and reduce socio-environmental vulnerabilities related to hydrometeorological hazards like flooding.

However, to effectively incorporate these changes into the local governance, sensible and non-imposing community and awareness processes adapted to local conditions are essential (Table 1: PR2). Many ejidos have factual authority in decision-making regarding watershed functions and seek to maintain certain autonomy. This authority can be viewed not as a deterrent but as an opportunity for developing non formal micropolicies that can be harmonized with broader official policy instruments (Table 1: PR5) in common agreements. Local decisions are important to ensure that final policies shall be practical and also culturally pertinent. Furthermore, with delegated power related to a view of citizen control (Arnstein, 1969), they can strengthen their legal recognition and financial mechanisms and engage in a more active and precise form in their territory’s surveillance and protection against both internal and external threats to watershed integrity (Table 1: PR7). This process can be associated with collaborative plans and projects elaborated with local subdelegates and other governmental authorities to establish activities tailored to their specific needs and capacities beyond rigid and non-culturally sensitive payments for environmental services and other restrictive environmental compensation mechanisms.

Within this framework, local communities can also become the foremost communication hubs, providing continuous monitoring and feedback to government authorities, thus enabling the iterative improvement and fine-tuning of watershed and environmental management policies over time (Table 1: PR8). This collaborative approach assures that policy development remains responsive, dynamic, and inclusive, incorporating key governance elements like transparency, stakeholder engagement, and receptiveness to feedback (Table 1: PR12)

At the municipal level, the government has the authority to formulate, conduct, and evaluate environmental policies through the Local Ecological Management Program (POEL) (Article 8, LGEEPA; DOF, 2021; Article 8, LPADSEQ; Periódico Oficial Del Gobierno Del Estado La Sombra de Arteaga 2009). Furthermore, it manages land use and oversees environmental conservation and protection, ensuring effective and sustainable local environmental management (Article 20 BIS 4, LGEEPA; DOF, 2021). These adjustments are made through the Ecological Managing Committee, which can facilitate the incorporation of specific activities related to monitoring integrity conditions at the CU scale, microwatersheds, and even clusters of microwatersheds as governance units or at the functional component scale.

As part of a monitoring program, it is necessary to carry out an annual update exercise on the functional conditions of the determined governance unit and all the technical implications that this entails. While one of the POEL strategies states the need to take actions to protect and conserve surface and groundwater resources from watersheds and hydrological microwatersheds in the territory, the indicator is ambiguously limited to the “number of actions taken.” On the one hand, there is a lack of updated and detailed information regarding the conditions and characteristics of riparian corridors, aquifers, as well as other biophysical elements and socioeconomic situations. Therefore, it is necessary to strengthen the monitoring and research of the mentioned elements. On the other hand, it is necessary to integrate appropriate performance indicators for POEL strategies. These indicators could be linked to achieving better levels of integrity in the sub-indices of one or more functional components of a CU. In our study, we recommend at least CHEM and HABT, which showed greater sensitivity to human activities. It is necessary to generate scenarios about the behavior and impact of stressors affecting the integrity of the watershed, as well as intervention or restoration scenarios. These feedforward mechanisms (Lorenzón, 2020) will allow more precise decision-making procedures to intervene in the watershed.

Also, the POEL must include conservation and restoration processes, not only linked to the recovery of riparian zone vegetation but also aimed at recovering the fluvial space and its natural hydrogeomorphological processes (Ollero and Romeo, 2007). Additionally, the environmental regulation criterion known as “sustainable water management (CMA)” should be associated with achieving greater control over activities such as the management of road and stream intersections, modifications to the riparian ecosystem linked to infrastructure, loss of riparian forest related to invasive and productive practices, diffuse pollution, among other situations that affect riparian zones and rivers.

Moreover, the Environmental Impact Assessment may provide a direct structure to link the territorial planning process and the legal framework (Parker and Aedo, 2021), like Local Ecological Planning, using this proposal as a mechanism to evaluate watershed impacts. These assessments represent a middle ground between local or even large-scale planning instruments directly related to watershed function and structure including the opportunity to establish compensation and mitigation measurements to prevent or reverse such impacts.

Upon reviewing the results obtained from the interviews and revisiting some principles of governance, such as the ideas of collaboration and participation (Camus, 2012) and fostering multi-level cooperation (OECD, 2015), a significant obstacle emerges. Not only is the concept of the watershed which is not properly integrated into the environmental policy instruments at local or state levels or is isolated from local governance processes, but rather the processes of interaction and collaboration between the different levels of government regarding the management of the watershed are not consolidated and the official forums for nongovernment stakeholders and authorities participation and representation at various scales of the watershed: Watershed Council (basin/watershed); Watershed Commission (subwatershed), and; Watershed Committee (microwatershed) show weak involvement and underrepresentation in the consultation processes presented in Article 20 of the Planning Law (DOF, 2023c). Regarding the Local Ecological Planning processes, the participation of these bodies is not mandatory, and this condition is reflected as no implementation of specific participative methodologies for involving informed participation of the social sectors, at least in watershed issues, which leads to weak and tokenized citizen participation. Moreover, many of these official forums are inactive or do not meet due to a lack of financial resources, political disinterest, and ambiguities in their responsibilities and operational forms, or they evolve through a strategic game of interests (Pérez Luján and Fuerte Celis, 2019).

To overcome these adversities, it is necessary to establish arrangements in terms of intersectoral collaboration between authorities within Watershed Councils, Commissions, and Committees and all sectorial actors that comprise them, not only in concertation and evaluation but in decision-making. This is crucial considering that these collegiate bodies form a multi-level system of collegiate organizations, from the Watershed Councils at the national level to the Commissions and Committees at the subwatershed and microwatershed scales, with the aim of promoting informed and co-responsible citizen participation in the integrated management of water resources in Mexico. (Article 14 BIS, LAN; DOF, 2023b). This form of collaboration should not only be aimed at strengthening decision-making but also at strengthening processes of informed social participation by integrating sectors of users and interested citizens into decision-making.

CONCLUSION

Our study successfully determined the overall integrity of LMW in terms of its functional components while also identifying specific impacts that help explain some of the causes affecting the condition of its nested elements. It was possible to determine that one or several functional sectors of the same stream or multiple CUs exhibited poor integrity conditions in a particular functional component, as well as the different stressors that caused the degradation.

The small area of LMW allowed for a more in-depth analysis of the underlying causes of the integrity conditions. By using indicators that provide greater fidelity regarding the hydrogeomorphological conditions in the LWM streams, it was possible to observe specific impacts at specific points. Furthermore, by considering the interaction of these stressors from a perspective of aggregate impacts, taking into account their spatial accumulation and negative synergies, it was possible to clarify the multiple activities deemed detrimental to the ecosystem functioning of the microwatershed. When studied individually, these might be considered to have mild impacts. However, when considered as integrated and in aggregate, they were not innocuous to integrity. Therefore, it is of utmost importance to address these interactions in relation to the study of ecosystem conditions in watersheds, whether in the scientific realm, in processes related to conservation and rehabilitation, or in other aspects related to environmental governance.

Human activity does not follow a mechanical process, and its actions stem from structures or configurations that influence their behavior and decision-making regarding the use of services derived from ecosystem functions. The stressors and indicators chosen for the analysis and study design considered in detail the influence of human activities on each functional complement of the watershed as a system. However, within the context of environmental governance, it is necessary to consider the concept of integrity and the development of the index as elements of a convergent science exercise. This requires the generation of complementary studies that, together with various social sectors, stakeholders, and strategic decision-makers, allow for a deeper understanding of the history and relationship of watershed integrity conditions with social, economic, political, or cultural dynamics. In other words, the “black box” of the watershed needs to be made transparent in order to influence certain aspects of its configuration that enable greater socio-environmental symmetry. Considering external factors beyond the biophysical realm of ecosystems not only relates to the behavior of the inhabitants of the localities but also to organizational matters and the perspective and political interests of decision-makers and stakeholders.

We emphasize that, in terms of legislation and environmental policy, Mexico would benefit from regulatory laws and instruments that effectively protect watershed integrity through efficient mechanisms related to extensive environmental and water monitoring, law enforcement, sustainability, and compliance, especially concerning riparian ecosystems or water management mechanisms at the state or national scales. This situation becomes evident when these policies are centralized and focused on achieving predetermined anthropocentric environmental health conditions oriented towards the provision of ecosystem services and monetized value assessments, which differ from the broader notion of integrity. The IWI/ICI can help our environmental authorities design a genuinely focused watershed perspective in environmental policy instruments like the POEL. Firstly, it can develop a baseline diagnosis that effectively considers the key functions of the watershed, with even greater emphasis on functions such as regulation and hydrological connectivity, as well as the importance of riparian corridor conditions in the watershed, which generally go unnoticed in these instruments Also, it allows for a zoning and prioritization process with greater precision, both protection of critical CUs or microwatersheds and for rehabilitating others in a degraded condition. As well as guide specific strategies and policies with an objective and scientific watershed perspective; likewise, the implementation of the index provides clear indicators related to each stressor and how efforts to address them or their neglect can be quantitatively expressed both individually and in terms of their impact on the key functions of the watershed.

Research Impact Statement:

Biophysical degradation and water challenges in México require environmental governance processes that use precise instruments for assessing and managing the functional conditions of the watersheds.