Some of the existing graduate courses are listed below, but there are many others!
Groundwater Hydrology
Environmental Geochemistry
Chemical Hydrogeology
Numerical Modeling of Groundwater Flow
Advanced Topics in Hydrogeology, examples include:
Karst Hydrology
Geostatistics
Reactive Transport
Regional Groundwater Flow
Advanced Topics in Geochemistry, examples include:
Geochemical Kinetics
Geochemical Thermodynamics
Shales: Energy and Environment
Simulation and Modeling in Geosciences
Environmental Chemistry
Engineering Aspects of Water Quality
Techniques for Environmental Analysis
Environmental Engineering Microbiology
Advanced Hydraulics
River Mechanics and Sediment Transport
Surface Water-Groundwater Interactions
Environmental Monitoring and Sampling
Dynamics of Groundwater
Transport Processes in Waterways
Transient Flow in Hydraulic Systems
Environmental Soil Chemistry
Bioremediation
Remediation of Mined Lands
GIS for Engineers
Field Methods in Hydrology
Forest Soils and Hydrology
Flow and Transport in Petroleum Reservoirs