This fact sheet presents and explains some common concepts in hydrology and the hydrologic cycle. The science or study of hydrology focuses on the distribution, occurrence, circulation, and properties of water in the environment.

This publication explains the essential physical and hydrologic properties that control how soils store and move water. It describes how texture, structure, pore size, bulk density, and organic matter determine infiltration, drainage, and the distribution of water within the soil profile. The concepts of water content, water potential, and the distinction between gravitational, plant‑available, and tightly held water are outlined in relation to various soil textures. It also introduces soil drainage classes and the water‑balance framework, linking precipitation, evapotranspiration, runoff, and percolation to seasonal soil‑moisture dynamics. Together, these principles provide a foundation for informed decision‑making in crop production, irrigation scheduling, nutrient management, and long‑term soil and water conservation.

This publication highlights recent advances in adapting denitrifying bioreactors developed in the Midwest to the Mid-Atlantic region. Denitrifying bioreactors are edge-of-field management practices that harness the activity of soil bacteria to remove excess nitrogen from drainage waters. Agricultural drainage is a significant source of nutrients to the Chesapeake Bay and important to manage. Although challenges remain with respect to adapting designs to treat ditch drainage, denitrifying bioreactors hold promise to yield water quality improvements in the Chesapeake Bay watershed.

Denitrifying bioreactors (DNBRs) are an alternative best management practice (BMP) that can reduce the amount of nitrogen reaching surface waters. DNBRs function by supporting soil microorganisms that are capable of denitrification in a favorable environment.