Numerous regional approaches to calculating maximal water discharges have led to their classifica tion (separately for rain floods and spring floods) pre sented in [7]. The formulas for maximal spring flood runoff, in their turn, are divided into two groups:(1) reduction formulas, explicitly reflecting the reduction of unit area spring flood discharges with increasing watershed size;(2) volumetric formulas, expressing the maximal water discharge as a function of the flood volume, its duration, and geometric shape.By their structure and content, maximal runoff formulas for rain floods are divide into four groups:(1) based on the maximal rainfall rate over the design travel time τ;(2) reduction structures;(3) calculation methods based on hydromechanical theories;(4) volumetric formulas.In the general form, the formula of limiting inten sity can be written as:(1)where are ordinates of reduction curve of mean precipitation intensity over the design time τ, H d is the daily maximum of rain, η is an overall runoff coeffi cient.The formulas relying on hydromechanical theories of storm runoff are based on equations of dynamic equilibrium and continuity of runoff for elementary areas or on models of channel isochrones (for watersheds of any size). In the general form, A.N. Befani [1] derived the following basic equation:(2)where ω is the cross section of an open flow, ω f is the cross section of a floodplain flow, ω а is cross section in alluvium, δ is the free porosity of alluvium.With some simplifications, such as assuming a lin ear relationship between ω, on the one hand, and ω f and ω а , on the other hand, integration of (2) yielded a generalized structure of the calculation formulawhere Y m is runoff depth, t c is channel travel time, ϕ is a coefficient of completeness of slope inflow, contrib uting to the formation of q m ; at t d < T 0 ,T 0 is the duration of water inflow from slopes into channel network, k h is hydrographic coefficient; at t c < T 0 ,d 0 ' ; t t q dt ϕ = 1.0, = ∫ ∫ h c h m 0 0 ' , ' t t t t t q B dt k B q dt WATER RESOURCES AND THE REGIME OF WATER BODIES Abstract-Scientific and methodological approaches to calculating characteristics of maximal runoff in Ukrainian rivers are considered.