INTRODUCTION:
Groundwater depletion drains aquifers supporting irrigation, drinking water, and economies, yet healthcare access implications are incompletely captured by public health surveillance.1,2 In groundwater-dependent regions, water stress may precede healthcare system strain by reshaping agricultural viability, population stability, and service demand before morbidity and mortality signals emerge. 3 The High Plains Aquifer (~450,000 km²) provides a well-instrumented reference case to compare healthcare access vulnerability in groundwater-dependent regions.4

METHODS:
We developed a county-level, cross-sectional surveillance framework in western Kansas assembling a dataset across domains: groundwater exposure and dependence, climate stress, socioeconomic and language barriers, service availability and redundancy, and geographic accessibility to hospital, emergency, and obstetric care. Indicators were fixed a priori and maintained in a registry for reproducibility and cross-setting comparison. The staged framework includes Tier 1 exposure classification via polygon intersection with the High Plains Aquifer; Tier 2 domain population to characterize access configurations; and Tier 3 computation under facility-loss scenarios to quantify shock sensitivity. Unlike composite indices, domains are not collapsed into a single score, preserving surveillance of structural access conditions.

RESULTS:
Tier 1 identified 56 aquifer-exposed counties with heterogeneity in aquifer overlap, demonstrating feasibility of exposure classification. An indicator registry and preliminary Tier 2 integration has been established, including socioeconomic and language-access indicators and an inventory of hospitals, emergency departments, and obstetric services. Climate stress, groundwater dependence, and accessibility metrics are in advanced integration.

CONCLUSIONS:
This framework supports surveillance of healthcare access vulnerability in groundwater-dependent regions by tracking configurations that may shift under upstream water stress. 5 Early changes may manifest as service contraction, rising travel burdens, and socioeconomic strain.3,5 Using reproducible, cross-sectional indicators from public and administrative data, the framework can screen for configuration shifts without reliance on outcome-based measures or prospective modeling. This work documents preliminary methods to support future utilization in other groundwater-dependent regions.