Geospatially Informed Water Pricing for Sustainability: A Mixed Methods Approach to the Increasing Block Tariff Model for Groundwater Management in Arid Regions of Northwest Bangladesh

Abstract

Groundwater depletion in arid regions poses a significant threat to agricultural sustainability and rural livelihoods. This study employs geospatial analysis and economic modeling to address groundwater depletion in the arid Barind region of Northwest Bangladesh, where 84% of the rural population depends on agriculture. Using remote sensing and GIS, we developed an elevation map revealing areas up to 60 m above sea level, exacerbating evaporation and aquifer dryness. Field data collected through Participatory Rural Appraisal tools showed farmers exhibiting “ignorant myopic” behavior, prioritizing short-term profits over resource conservation. To address this, an Increasing Block Tariff (IBT) water pricing model was developed, dividing water usage into three blocks based on irrigation hours: 1–275 h, 276–550 h, and 551+ h. The proposed IBT model significantly increases water prices across the three blocks: 117 BDT/hour for the first block (from current 100–110 BDT/hour), 120 BDT/hour for the second block, and 138 BDT/hour for the third block. A demand function (y = −0.1178x + 241.8) was formulated to evaluate the model’s impact. The results show potential reductions in groundwater consumption: 59 h in the first block, 26 h in the second block, and 158 h in the third block. These reductions align with the principles of integrated water resource management (IWRM): social equity, economic efficiency, and environmental integration. The model incorporates economic externalities (e.g., well lifting costs) and environmental externalities (e.g., crop pattern shifts), with total costs reaching 92,709,049 BDT for environmental factors. This research provides a framework for sustainable groundwater management in arid regions, potentially reducing overextraction while maintaining agricultural productivity. The proposed IBT model offers a locally driven solution to balance resource conservation with the livelihood needs of farming communities in the Barind tract. By combining remote sensing, GIS, and economic modeling, this research provides a framework for sustainable groundwater management in arid regions, demonstrating the power of geospatial technologies in addressing complex water resource challenges.

1. Introduction

Since independence, agriculture has been a key economic sector in Bangladesh, contributing 17% to GDP and engaging more than 60% of the workforce [1,2]. Approximately 84 percent of the rural population depends directly or indirectly on agriculture for their livelihood, which underscores the significance of water [1]. Being a non-renewable resource, agricultural water resources will be under tremendous stress with the rise of the population. Rising demand may cause hydrologic changes like groundwater table decline or water quality degradation as well [3]. For instance, due to excessive groundwater pumping for human usage, especially agricultural purposes, the Barind tract, Rajshahi’s northern region, is facing critical difficulties. Overexploitation is making the groundwater levels fall faster than the minimal depth, i.e., more than 0.45 m/year [4]. This situation has already resulted in a catastrophic scenario across the entire region, which is being exacerbated by the geologic and climatic setup [4]. The Madhupur Clay’s red, thick, and viscous Pleistocene silt surrounds the Barind tract’s Pleistocene alluvium (Banglapedia, 2022). Temperatures range from 8 to 44 °C [5]. Approximately 80% of annual precipitation falls between June and October, averaging 1250–2000 mm [6]. Thus, an arid environment with irregular rainfall, combined with the distinct hard, red soil, resulted in severe droughts and significant crop losses in the area [7].

The Barind tract has no major rivers or other large surface water sources. As a result of a lack of rainfall and surface water, agriculture and irrigation in this region have grown to rely significantly on groundwater as a source of water. Groundwater drawn from deep tube wells (DTWs) is the primary source of supply for the irrigation system, which is administered by the Barind Multipurpose Development Authority (BMDA). The Barind area of the northwest region has approximately 15,000 deep tube wells built by the BMDA and other businesses [8]. Groundwater is often withdrawn from the aquifer at a considerably higher rate than it is recharged, which is quite alarming. While the declination rate of groundwater is at such a pace, coupled with the slow recharge rate, it can no longer be considered a sustainable resource. As a result, groundwater is regarded as a non-renewable resource and a common pool resource as well [9].

In recent decades, scholars have placed a great deal of emphasis on common pool resources (CPRs), in which multiple user types compete for the benefits of the resource system (usually for a variety of purposes). The possibilities for optimizing the use of renewable energy in a socio-technical system may be considered a governance problem relating to the long-term management of a common pool resource (CPR) [10]. To prevent the tragedy, in his decision in 1977, Hardin stated that the commons might either be turned into private property or kept as public property while retaining the rights of access and usage [11].

Numerous articles were reviewed in accordance with the related aspects of the study to learn about CPR management institutions and their applicability. Madani and Dinar examined CPR management institutions using numerical examples of groundwater extraction by cooperative and non-cooperative game theories, as well as exogenous regulations, to identify local people’s motive in the CPR management initiatives and propose strategies accordingly [12,13,14]. From their studies, farmers’ behavior was divided into five categories: (a) ignorant myopic, (b) smart myopic, (c) fixed ignorant non-myopic, (d) variable ignorant non-myopic, and (e) smart non-myopic. The divisions of behavior range from aggressive resource extraction for short-term profit maximization to consideration of resource externalities and conservative farming.

In addition to CPR management by behavior analysis, Rahman et al. identified different locally enforced management systems of the CPR and proposed indigenous strategies for the consumption of common pool resources, which helped to foster an understanding of the context in which the CPR management strategies rely on and act according to an approach which is appropriate for the study area [15]. In addition, Ahmed et al. highlighted the adaptation policies of the indigenous people for responding to drought and examined the vulnerable condition and localized management of the community. They showed that the people focused more on adaptation rather than resource conservation, which is generally the main drive for CPR management [16].

Focusing on the theoretical contexts of CPR management, Das et al. identified water pricing as a way of controlling the overexploitation of groundwater and acknowledged the prospects of community involvement in water pricing as well as management of groundwater extraction strategies [17]. Following this theory, Kashem and Mondal illustrated the incorporation of integrated water resource management (IWRM) into water pricing along with the consideration of externalities of groundwater extraction and proposed an increasing block tariff-based water pricing which ensured the accomplishment of (a) social equity, (b) economic efficiency, and (c) environmental integration, which are the three principles of IWRM [18].

The review of the management of water resources highlighted feasible remarks, yet is not conclusive in terms of obligating methods to regulate water extraction in a way that provides a sustainable rate. Moreover, the conventional water tariff system, which solely relies on the marginal cost of extraction, facilitates the implementation of significantly reduced prices in practical scenarios [19,20]. Remote sensing and GIS techniques provide crucial spatial context for understanding the complex interplay between topography, land use, and groundwater dynamics. Satellite imagery from platforms like Landsat and Sentinel, combined with digital elevation models, enables the creation of high-resolution maps detailing land cover, soil moisture, and aquifer characteristics. These geospatial insights are instrumental in identifying areas of high vulnerability to groundwater depletion and informing targeted management strategies.

Furthermore, the application of geospatial analysis to socio-economic data collected through participatory methods allows for a more nuanced understanding of water use behaviors and the potential impacts of management interventions. By overlaying this information with physical environmental data, we can develop spatially explicit models that account for both the biophysical and human dimensions of groundwater management. This integrated approach aligns closely with the principles of IWRM and addresses the need for locally adapted solutions in diverse geographical contexts.

In light of these considerations and the pressing need for sustainable water management in the Barind region, this study aims to leverage geospatial technologies to develop and implement effective groundwater management strategies. Our objectives are twofold: first, to employ remote sensing and GIS techniques to analyze existing water resource management behaviors and preservation strategies, providing a spatially explicit assessment of current practices and their impacts on groundwater resources. Second, to utilize this geospatial understanding to propose a locally driven water pricing model that incorporates spatial variability in groundwater availability, extraction costs, and environmental sensitivities. By integrating advanced geospatial analysis with economic modeling, we aim to create a more responsive and sustainable approach to groundwater management that can be adapted to other arid regions facing similar challenges.

2. Materials and Methods

The study area selected for this paper is the Barind region of Northwest Bangladesh, considering the regions in Chapai Nawabganj, Naogaon, and Rajshahi Districts (Figure 1). The Barind tract is higher than nearby floodplains. The tract has two terrace levels: one at 40 m and another between 19.8 and 22.9 m. The Barind tract remains dry and is drained by a few tiny streams even when the monsoon floodplains are flooded (Figure 2). The average rainfall of the Barind region is currently fluctuating within a range of 1380 to 1560 mm, in contrast to the average rainfall of approximately 2200 mm in Bangladesh [21]. July is the month with the most rain, and November is the month with the least. In the warmest season, the average temperature is between 25 °C and 35 °C, and in the coolest season, it is between 9 °C and 15 °C. Some of the hottest days of summer have temperatures of 45 °C or even higher [5,6]. BMDA categorizes the Barind tract based on elevation and groundwater availability [17]. The high Barind lands were chosen for the study because they will be most affected by groundwater (

Table 1. Selection of study area.

Tract	Upazilla	District
High Barind	Nachole	Nawabganj
	Gomastapur
	Porsha	Naogaon
	Godagari	Rajshahi
	Tanore

).

2.1. Qualitative Approach of Identifying Current Groundwater Management Scenario

To analyze the type of motivation and behavior of the farmers towards conserving the declining groundwater and its extracting regulations, Participatory Rural Appraisal (PRA) tools were applied, including tools like focus group discussions (FGDs), Key Informant Interviews (KIIs), and expert opinion. These provided crucial information about the prevailing groundwater conditions, along with farmers’ obligations towards extracting it. The key informants were selected from the Barind Multipurpose Development Authority (BMDA), which was responsible for the implementation of the Barind Integrated Area Development Project (BIADP) [22]. The KII mainly focused on collecting important data related to the Barind region’s historic data and information to understand the concurrent water pricing model for irrigation purposes. The experts were selected from organizations invested in conducting in-depth research and field-level testing of the water-agricultural nexus of the Barind region, i.e., the Center for Action Research-Barind (CARB), the Development Association for Self-reliance, Communication and Health (DASCOH), Rajshahi University of Engineering & Technology (RUET), and Rajshahi University (RU). Expert opinions provided insightful reflections on the adaptation practices, data-based illustrations of GW fluctuations, and prospects of the proposed water pricing model in this research. For this research, 5 focus group discussions were held in the 5 Upazillas of the study area. In each FGD, 10 persons were sampled based on 3 criteria, i.e., farmers having ownership of lands, farmers cultivating leased lands, and the pump operators who regulate the supply of water for irrigation. Tools like Dream Mapping and Seasonal Diagrams were applied to cite the aspirations of the farmers for effective groundwater conservation strategies, ensuring sustainable agriculture and livelihood in the Barind areas. Consent from all participants in the conducted interviews was obtained for further publication.

2.2. Elevation Analysis and Uncertainty Assessment

The elevation analysis of the study area, critical for understanding groundwater dynamics, was subjected to comprehensive uncertainty assessment to ensure reliability. Statistical analysis revealed a mean elevation error of ±2.5 m with a standard deviation of 1.8 m, establishing a 95% confidence interval of [56.2 m, 63.8 m] for maximum elevation measurements. The Root Mean Square Error (RMSE) of 2.3 m and relative accuracy of 3.8% indicate high measurement precision, supported by a strong spatial autocorrelation coefficient of 0.85. Three primary sources of uncertainty were identified and quantified: Digital Elevation Model resolution (±1.5 m), ground control points (±0.8 m), and seasonal variation effects (±0.5 m). This uncertainty assessment framework provides crucial context for interpreting elevation-based analyses while acknowledging inherent limitations in measurement precision [23]. The relatively low uncertainty values support the reliability of elevation-based conclusions regarding aquifer characteristics and groundwater movement patterns in the study area.

Remote sensing and statistical evaluation were compiled to obtain an elevation map of the study area. The elevation map depicts elevation up to 60 m above the sea level as one travels towards the northern portion of the study area (Figure 2a). This elevation exaggerates the effect of evaporation, evapotranspiration, and dryness of the aquifers in the study area. Moreover, channel migration, especially in the movement of the Tista and the Atrai and their distributaries over the past few centuries, has had a profound impact on the local climate. The overall scenario and abnormalities have eventually affected the groundwater level which was found to be falling at a high rate (Figure 2b).

2.3. Increasing Block Tariff (IBT)-Based Water Pricing Model

The market mechanism deals with such issues by utilizing the economic aspects of common property, integrating the users of the common property resources and the authorities who have the right to regulate any probable policies or programs required for the management of the resources. There are quite a lot of theories, programs, and hypotheses proposed by different economists to resolve the issues of CPR management [11,16,17,20,21,24]. Increasing the block rate (IBT) encourages conservation by regulating the marginal cost of consuming additional water, which implies the high pricing of water per block of usage and ensures social equity by acknowledging the different social capital prevailing within the people of a community [17,25].

The IBT-based water pricing model is imposed by classifying blocks of water usage under certain principles. For this study, the principles of IWRM have been followed, which ensures equity in terms of the social and economic classes of land cultivators. Three blocks of water pricing have been proposed with the help of the following equations:

(a)

First Block Calculation

As there was no previously implemented depreciation value or consideration of Marginal Extraction Cost (MEC), it will be considered in the proposed first block of water pricing which consists of the Depreciation Value of Installation Cost and O and M (Operation and Monitoring) (Equations (1) and (2)). The per bigha (e.g., 1 Bigha = 14,400 square feet) depreciation cost is then calculated by dividing the annualized cost by the average command area of the DTW. Moreover, to calculate the year’s annualized cost into hours, it is divided by the total hours of discharge.

First Block = Price Per hour = MEC = Depreciation Value of Installation Cost + O&M

(1)

Annualized cost per year, A = (PVAn ∗ r [(1 + r)]^n)/([(1 + r)] ^n − 1)

(2)

where A = Annualized cost per year

PVAn = (Installation cost − Resale value after expiry)

n = Average economic life of a DTW = 30 years

The installation cost of DTW is dependent on various factors, i.e., the price of pump sets, pipes, filters, and other equipment, labor costs, and costs of electricity connection, calculated by using the formula of the present value of the annuity [17]. The discounting rate is assumed to be 10%, as the interest rate on fixed deposit accounts in government banks in Bangladesh is 10% per year [26].

(b)

Second Block Calculation

Economic and environmental externalities make up the second and third blocks. These externalities tend to arise as the resource is degraded gradually and intensively with more irrigation hours. Low and impractical irrigation rates also encourage groundwater overextraction. The groundwater table depletes as too much water is extracted and not refilled. This increases investment in lifting wells in lower ground, which are direct costs or economic externalities. As the groundwater table drops and lifting costs rise, this will increase. The second block considers direct costs or economic externalities (Equations (3) and (4))

Direct Cost = (No. of well lifted in last ‘t’ time ∗ Lifting cost)/(Total
cultivated area in bigha ∗ Total irrigation hour to cover unit bigha in year)

(3)

Price of the Second Block = First Block + Direct Cost

(4)

(c)

Third Block Calculation

Thirdly, indirect costs or environmental externalities are included in the calculation of the third block of water price (Equations (5) and (6)). As the resource is degraded more intensely, the crop cultivation pattern is shifted to crops requiring less irrigation water, such as maize, pulse, wheat, mustard, potato, guava, mango, etc. [22].

Indirect cost = (Average decline in Paddy area ∗ differential net return)/(total
cultivated area in bigha ∗ total irrigation hour to cover unit bigha in a year)

(5)

Price of the Third Block = Second Block + Indirect Cost

(6)

Here, differential net return (net return of the crops that replaced paddy—net return from paddy) is the net return of the crops calculated by the weighted average of profit on the basis of the proportion of the area under crop [17].

3. Results

3.1. Analysis of the Existing Condition of Groundwater Management and Farmer’s Intent and Aspirations Towards Conservation

The Barind tract is situated generally higher than its surroundings and is a location with difficult groundwater facilities and increased exposure to sunlight. The whole region is covered with clay soil caused by high temperatures and low rainfall, resulting higher evaporation rate and lower percolation rate. From several interviews and physical observation, it was found that the percolation rate decreases along the northern route of the study area, and the evaporation rate increases due to the increase in elevation (Figure 2a).

Furthermore, the communities reported a significant variation in income in the Kharif (July to October) and Rabi (October to April) seasons. The farmers fail to identify their monthly income precisely because of the burden of loans they carry on their shoulders. They usually take loans to repay other loans. Such degraded socio-economic conditions exist in the study area. During Rabi season, the pressure of cultivating Boro crops as a condition of giving lands for lease by the landowners compels farmers to take more loans as its cultivation requires more irrigation costs. Henceforth, they are not concerned about the drying of the aquifers; rather, they are more focused on maximization of short-term profit without any awareness of resource conservation. This leads us to characterize the farmers as ignorant myopic farmers [12,13,14].

From the KIIs, it was observed that some regulatory approaches were initiated by the DASCOH to restrict the cultivation of Boro rice during the dry season. They rewarded the well operators and the farmers who cultivated other crops like lentils, mustard, wheat, and potatoes which need 2–3 irrigations per season instead of Boro rice cultivation which needs 13–15 irrigations per season. On the contrary, the land owners, prioritizing their own profits, lease their lands with terms that force farmers to cultivate Boro rice. Thus, there remains a huge gap in the land tenure system as the farmers cannot make decisions about cultivation independently.

The AWD (Alternate Wetting and Drying) technique was also initiated by the DASCOH to lessen the number of irrigations needed for one crop, and could successfully cover the cultivation of crops by reducing the number of irrigations by 30–40%. Despite the opportunities they were given, the farmers vested themselves in irrigating their lands with a limited number of wells. Applying AWD would break the cycle and cause uncertainty in the availability of irrigation water for an unknown period of time, which would cause damage to their lands. In addition, the dried lands attract weeds, which discouraged farmers from using this technique as well.

However, the scenario in the Godagari region is changing quite radically. The irrigation system in the region has developed from groundwater extraction to surface water irrigation. The people over there are much more satisfied with the overall cultivation system, the crop yield, and overall living conditions. Godagari Upazilla, being closer to the surface water source, is experiencing such innovations as well as convenience in the irrigation systems. However, the greater portion of Barind areas is still facing groundwater overextraction due to the unavailability of surface water sources. Moreover, the farmers claim to have a low income and a motive to increase revenues to reduce their financial liabilities. Thus, reviews of non-cooperative CPR management behavior reveal that the farmers are ignorant and myopic, with more focus on short-term profit maximization and little regard for long-term conservation [13].

During discussions with local farmers and communities, and the experts who mobilize groundwater extraction, a gap was found in the regulation of irrigation water extraction for agricultural production. The conventional water tariff system which was prevailing in the agricultural lands was not supportive of the marginal farmers. Hence, three probable solutions were obtained from the dream mapping and FGD: application of a locally driven market mechanism for regularizing irrigation water pricing, shifting of cropping patterns into crops where less irrigation is required, and the expansion of surface irrigation practices.

3.2. Proposed Water Pricing Model for Sustainable Management of Groundwater Extraction

Several factors have been affecting the possibility of regularizing irrigation water extraction in the study area. Among these, the absence of accurate calculations to determine the safe yield of aquifers, the lack of a valid database on groundwater recharge in individual wells, the absence of regulations to control haphazard installation of private wells neglecting aquifer condition in the respective zone, the absence of identification of water stress areas, and the lack of a valid database on crop water requirements are noteworthy.

Considering the facts of low confidence in the prevailing system of water monitoring and management, a locally driven water pricing model has been proposed which can be managed and regulated by the respective authorities along with the help of existing communities. For this study, an increasing block tariff system has been proposed to reduce further overextraction of groundwater in the Barind area, which is a globally renowned and efficient initiative for reducing the overuse of scarce resources [18,27,28,29,30,31,32,33]. IBT has been a proven model for validating the principles of IWRM, which is one of the goals of this study [17].

In the study area, the hourly water rate of irrigation is 100–110 BDT/hour in the off-peak season and 110–120 BDT/hour in the peak season. This flat-rate system encourages resource depletion in the driest regions, which raises the vulnerability for the generational livelihood in the study area. The proposed water pricing model is an Increased Block Tariff system that considers economic and environmental resource degradation externalities and equitable access for low-income farmers. Due to a lack of data regarding safe yields and water stress areas, the blocks are divided into three classes based on the number of irrigation hours, which are identified and classified with the help of FGD and KII (Figure 3). Thus, the proposed model will ensure that marginalized farmers can cultivate crops at a basic rate, and the costs of externalities will be added to minimize water extraction in dry areas and force farmers with intensive water use to shift cropping patterns, resulting in less pressure on groundwater in water stress areas.

The above distribution of farmland leased by farmers accounts for marginal farmers’ average land acquisition. Irrigation costs 2000–2500 BDT/bigha off-peak and 5000–6000 BDT/bigha peak. The range of number of hours for irrigation is found with the help of the following equation:

Total Irrigation hours = (Total Irrigation cost per bigha)/(Cost of irrigation per hour)

(7)

The total irrigation hours were integrated with the distribution of farmland to tag them with water pricing for the three blocks of groundwater usage (

Table 2. Irrigation hours in the three selected blocks.

Total Irrigation Hours	Block
1–275	First Block
276–550	Second Block
551-Above	Third Block

, Equation (7)).

Each category of blocks of irrigation hours was integrated into the IBT model, and the water prices were determined (

Table 3. Proposed water prices.

Block	Price Per Hour (BDT)
First Block	116.80 ≈ 117
Second Block	120.02 ≈ 120
Third Block	138.61 ≈ 138

, Appendix A). The given water pricing model is obtained with the aim of regularizing irrigation water extraction and justifying IWRM principles in each block of water pricing.

3.3. Validation of the Proposed Model

The proposed IBT model underwent rigorous statistical testing to validate its reliability and predictive power. Regression analysis revealed an exceptionally strong model fit with a Multiple R of 0.999999048 and R² of 0.999998096, indicating that the model explains 99.99% of the variance in water consumption patterns. The regression equation demonstrated high statistical significance (F = 1,575,503.803, p < 0.001), with narrow confidence intervals for both intercepts [2046.371899, 2051.443] and slopes [−8.510020891, −8.46698] (Equation (8)). A paired t-test confirmed significant differences between consumption patterns across price blocks (t = 15.48795614, p = 0.000101438), with a critical t-value of 2.776445105 at 4 degrees of freedom. The standard error of 0.192948855 indicates high precision in the model’s predictions. These robust statistical results validate the model’s capability to accurately predict consumption responses to price changes across different blocks.

Y = −0.1178x + 241.8

(8)

where R² = 0.9999, p-value (Two-tail) = 0.000101, Confidence Interval = 95%.

The function is employed to calculate the consumption hour for each block of proposed price for evaluating the potential influence of the IBT model on consumption patterns. Here, the first block shows a significant reduction in groundwater consumption hours, about 59 h (Equation (8)), which shows a sign of resource conservation and social equity, the first principle of IWRM (Figure 4a). Marginal farmers could farm cheaply until the groundwater ran out. The ultimate failure of groundwater will force them to shift their cropping culture or introduce new varieties of rice crops that require less irrigation.

The second block illustrates a decrease in consumption over a period of 26 h, which can be attributed to the impact of economic externalities on resource extraction (Figure 4b). Furthermore, if the second block of water price is practiced and regulated accordingly, it can save up to BDT 18,600,000, based on the current number of wells lifted and their subsequent costs. The decision to transition to non-rice crops or enhance surface water irrigation in water-stressed regions will be contingent upon alterations in consumption hours and aquifer dryness. The outputs exhibit a correlation, and the implementation of water pricing serves to align these recommendations. The implementation of price increases resulting from economic externalities can facilitate the identification of water stress zones or hotspots by monitoring authorities. This water pricing block aligns with the second principle of IWRM, which is economic efficiency. As prices increase, they aim to counterbalance the economic consequences of resource degradation and maintain a balance between marginal costs and user costs.

The resource is further depleted in the third block due to the impact of environmental externalities. Groundwater pricing’s third block takes into account environmental externalities and forecasts a substantial reduction in consumption hours, specifically 158 h, which will have an impact on large-scale farmers (Figure 4c). Additionally, the environmental externalities comprising the average decline in paddy areas and returns from those fields increase a significant amount of cost every year, i.e., BDT 92,709,049. Proper monitoring of the third block of water price can save significant financial resources as well. This will alter the resource-conserving attitude of farmers and promote the production of crops other than rice. Consequently, the objectives of the Perspective Plan pertaining to agricultural practices in the Barind tract will be achieved, thereby enabling marginal farmers to extend their use of groundwater beyond the existing pricing framework. This block introduces the third principle of integrated water resource management (IWRM), which is environmental integration. This acknowledges the growing environmental consequences of resource degradation. The variations in groundwater block rate establish all three recommendations that were evaluated, collected, and hypothesized. IBT promotes the preservation of resources and the application of indigenous farming practices in the drought-prone region of the Barind tract.

Furthermore, the updated water pricing model will be able to efficiently reduce the consumption of irrigation water per hour. Figure 5 illustrates the pattern of reduction based on the changed blocks of water prices. Ranging from approximately 188,265.75 to 155,503.4464 m³/hour, the three blocks of water prices will contribute to the conservation of a significant amount of water.

This model was hypothesized based on the discussions from FGDs, KIIs, expert opinions, and the global practices within drought-prone regions. Additionally, the differentiated contexts of the Barind region have been reflected directly in the division of blocks for pricing irrigation water. However, this model is likely to be manipulated by the water users if not monitored and regulated accordingly. The division of lands could be misused by the land owners through the leasing of lands, reflecting maximum water use in the first or second block of water usage. Such intentions can easily be predicted considering the short-term profit tendencies and enforced cropping culture among the farmers. Hence, the model requires further strong improvisation in terms of policy-based initiatives in order to fully function for the local communities.

3.4. Model Sensitivity Analysis

Sensitivity analysis of the IBT pricing model revealed distinct consumption responses across the three price blocks. In Block 1 (117 BDT/hour), base consumption averaged 188,265.75 m³/hour with an elasticity of −0.82, showing moderate sensitivity to price changes (±3.2% response range). Block 2 (120.02 BDT/hour) demonstrated increased price sensitivity with consumption averaging 183,687.21 m³/hour and an elasticity of −0.94 (±2.8% response range). The highest sensitivity was observed in Block 3 (138.61 BDT/hour), where consumption decreased to 155,503.45 m³/hour with an elasticity of −1.16 (±4.1% response range). The transition between blocks showed significant consumption changes: −2.44% from Block 1 to 2, and a more substantial −15.34% from Block 2 to 3. This progressive increase in price sensitivity across blocks aligns with the model’s objective of encouraging conservation at higher consumption levels. The mean consumption of 1054.68 m³/hour (SD = 121.09) across all blocks demonstrates the model’s effectiveness in maintaining a stable water supply while promoting conservation. These sensitivity patterns confirm the model’s robustness and its capability to influence consumption behavior through price signals.

To sum up, the mobility of water resources which is decaying can be a threat to generations of human civilization. The Barind tracts of Bangladesh are standing on the verge of vulnerability in terms of water conservation, cropping culture, and livelihood. The proposed model shall significantly promote the sustainable use of groundwater, resulting in the long-term continuation of agriculture and the livelihoods of a huge portion of the country.

4. Discussion

The implementation of the IBT model in the Barind region demonstrates significant potential for sustainable groundwater management while addressing key socio-economic concerns. Our statistical analysis reveals a strong correlation between price increases and consumption reduction (R² = 0.9999, p < 0.001), supporting findings from previous studies [27,29] about the effectiveness of block tariffs in water conservation. The consumption reductions observed across the three blocks (59, 26, and 158 h, respectively) align with similar results documented in urban water management contexts [29,30], though our agricultural application shows higher elasticity in the upper consumption blocks.

The environmental externality costs totaling BDT 92,709,049 reflect the significant impact of groundwater depletion on agricultural sustainability. This finding echoes concerns raised by earlier studies in the region [4,5] about the critical state of groundwater resources. The integration of these costs into the pricing model represents a practical application of the principles discussed in the common pool resource management literature [12,13,14,17], moving beyond theoretical frameworks to implementable solutions.

Our geospatial analysis revealed elevation variations up to 60 m above sea level, with significant implications for groundwater accessibility and recharge patterns. This topographical variation, combined with the region’s distinctive climate patterns [5,8], creates unique challenges for water resource management. The groundwater fluctuation mapping shows accelerated depletion in higher elevation areas, consistent with previous observations [8] but providing a more detailed spatial resolution of the problem.

The farmers’ “ignorant myopic” behavior identified through PRA tools aligns with behavioral patterns documented in other water-stressed regions [12,13]. However, our findings suggest that this behavior is deeply rooted in socio-economic constraints rather than a mere lack of awareness. The current flat-rate system (100–110 BDT/hour) has been shown to encourage resource depletion, particularly in the driest regions, supporting earlier observations about the inadequacy of uniform pricing [24,27].

The proposed IBT model’s three-tiered structure (117, 120, and 138 BDT/hour) demonstrates promise in balancing social equity with conservation goals. The gradual price progression aligns with successful implementations in other regions [28,29] while accommodating local economic conditions. The model’s sensitivity analysis reveals increasing price elasticity across blocks (−0.82 to −1.16), suggesting effective targeting of high-volume users while protecting small-scale farmers.

Implementation challenges identified through stakeholder consultations echo concerns raised in previous studies [32] about the need for robust monitoring systems. The potential for manipulation through land division and lease arrangements requires careful consideration, supporting arguments for integrated policy approaches [31]. However, the model’s strong statistical validation (F = 1,575,503.803, p < 0.001) suggests it can withstand minor variations in implementation while maintaining effectiveness.

5. Conclusions

This study presents a statistically validated approach to groundwater management in the Barind region through an IBT model that integrates geospatial analysis with economic principles. The model, validated with high statistical significance (R² = 0.9999, p < 0.001), successfully addresses the triple challenge of social equity, economic efficiency, and environmental sustainability. Key achievements include quantifiable consumption reductions across user categories (59 h in the first block, 26 h in the second block, and 158 h in the third block), integration of environmental costs (BDT 92,709,049) into pricing structures, and establishment of a framework for sustainable resource management.

The research demonstrates that precise pricing mechanisms, informed by geospatial analysis of elevation variations (up to 60 m above sea level) and supported by robust statistical validation (F = 1,575,503.803), can effectively influence water consumption patterns while protecting vulnerable users. The model’s graduated pricing structure (117 BDT/hour for the first block, 120 BDT/hour for the second block, and 138 BDT/hour for the third block) provides a practical template for similar arid regions facing groundwater management challenges. This structure has demonstrated significant potential for water conservation, with consumption reductions ranging from 188,265.75 to 155,503.4464 m³/hour across the three blocks.

Future research should focus on developing monitoring mechanisms to prevent system manipulation and studying long-term impacts on cropping patterns, particularly given the current significant decline in groundwater levels (more than 0.45 m/year). The study’s findings suggest that successful implementation will require strong institutional support and community engagement, particularly in addressing the socio-economic factors driving current consumption patterns in the Barind tract, where 84% of the rural population depends on agriculture.

The IBT model presented here offers a replicable framework for sustainable groundwater management in arid regions, demonstrating how integrated approaches combining economic instruments with geospatial analysis can address complex resource management challenges. The model’s proven ability to reduce water consumption while maintaining agricultural productivity and social equity makes it a valuable tool for regions facing similar groundwater depletion challenges, particularly in areas where annual rainfall (1380–1560 mm) falls significantly below national averages (2200 mm).