This article introduces a flow controller for an upstream water head designed for pipe culverts used in drainage ditches or wells. The regulator is applicable to water flow rates in the range of Qmin < Q < Qmax and the water depth H0, exceeding which causes the gate to open. Qmin flow denotes the minimum flow rate that allows water to accumulate upstream of the controller. Above the maximum flow rate Qmax, the gate remains in the open position. In the present study, the position of the regulator’s gate axis was related to the water depth H0 in front of the device. Derived dependencies were verified in hydraulic experiments. The results confirmed the regulator’s usefulness for controlling the water level.

The search for simple models of drainage–irrigation systems functioning and management has still been an important research objective. Therefore, we presented a conceptual model based on groundwater dynamics equation along with proper assumptions on water equivalent of transient porosity-i.e., storage in the soil profile based on the long-term experience of the research on drainage-sub-irrigation systems. Several parameters have been incorporated in the model to effectively and comprehensively describe drainage/irrigation time, leakage from the soil profile, the soil moisture content in the root zone, and the shape of the groundwater table on the drainage–sub-irrigation plot. The model was successfully validated on groundwater level data in ditch midspacing on an experimental site located within a valley sub-irrigation system with the advantage of a relatively simple representation of flows through the soil profile. The robust character of the conceptual equation of groundwater dynamics, as well as the approach to its’ parameters, were proved through a close match between the model and observations. This promotes the capacities of the proposed modeling procedure to conceptualize drainage-irrigation development with the impact of external and internal sources of water. The potential was offered for the evaluation of water management practices in a valley system influenced by horizontal inflows from surrounding areas as indicated by calibration results. Future challenges were revealed in terms of water exchange between the plots and validation of soil moisture content modeling.

The topic of the research is a specific feature of the region within a group of regions -the relative environmental validity of developing drainage and irrigation within it; relative, as it refers to the environmental validity of developing drainage and irrigation in regions belonging to a selected group of regions.The research revolves around the issue of the methodology for assessing (quantifying) the relative environmental validity of developing drainage and irrigation in a region (province). Developing such a methodology and presenting an example of its application is, thus, the aim of this work.The methodology comprises two parts. The first of them pertains to generic, e.g.: climate, soil-water, hydrological, etc. quantification of the relative environmental validity of developing drainage and irrigation in regions (provinces), while the second -the synthesis of these partial generic validities into one indicator -the relative environmental validity of developing drainage and irrigation in a region (province). When realizing the first part, indicators characterizing the partial validities for developing drainage and irrigation in subregions (districts) are used, whereas in the second -a fragment of the ELECTRE III multi-criteria dialogue method of ordering of variants.Based on the proposed methodology, the individual provinces of Poland were classified. The classification was carried out based on such generic validities for the development of irrigation as climatic, soil-water, hydrological and environmental-ecological validity. According to this classification, Opolskie Province is characterized by the strongest environmental validity of developing irrigation, whereas Małopolskie Province -the lowest.Preliminarily analyses confirmed the accuracy and reliability of the proposed methodology for assessing the relative environmental validity of developing drainage and irrigation in the provinces.

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