Дайджест ссылок

The Relationship between the Darcy and Poiseuille Laws. Попытка увязать закон Дарси (описывающий, как известно, течение жидкости в пористых средах) с законом Пуазейля (ламинарное течение жидкости в трубках) с помощью модели бочки, заполенной водой с песком и оборудованной сливной трубкой.

The Poiseuille and Darcy laws describe the velocity of groundwater flow under laminar conditions. These laws were deducted empirically in conduit and porous systems, respectively, and are widely used to model the groundwater flow. The analytical relationship between these hydraulic laws has been found by draining a tank-reservoir. Based on equations found, the discharge in a conduit under the Poiseuille law can be transformed in the same amount flowing inside a darcian system, and vice versa. This transformation occurs, for example, in karst aquifers, from the matrix to karst conduits during discharge phases, and from conduits to matrix during recharge phases.

FABDEM. Бесплатная для некоммерческого испозования модель рельефа, полученная из Copernicus GLO 30 Digital Elevation Model путем очистки от зданий и деревьев. Довольно грубая, к сожалению. В частности, там удалили не только деревья и здания, но и некоторые рукотворные холмы (несколько подмосковных свалок почему-то стали на 10-20 м ниже, чем есть на самом деле). Ну и в принципе артефактов постобработки там многовато.

FABDEM (Forest And Buildings removed Copernicus DEM) is a global elevation map that removes building and tree height biases from the Copernicus GLO 30 Digital Elevation Model (DEM). The data is available at 1 arc second grid spacing (approximately 30m at the equator) for the globe. The FABDEM dataset is licensed under a Creative Commons "CC BY-NC-SA 4.0" license.

The Radius of Influence Myth. А ведь я всегда говорил, что в формуле Зихардта что-то не то — слишком маленький радиус влияния получается.

Empirical formulas to estimate the radius of influence, such as the Sichardt formula, occasionally appear in studies assessing the environmental impact of groundwater extractions. As they are inconsistent with fundamental hydrogeological principles, the term “radius of influence myth” is used by analogy with the water budget myth. Alternative formulations based on the well-known de Glee and Theis equations are presented, and the contested formula that estimates the radius of influence by balancing pumping and infiltration rate is derived from an asymptotic solution of an analytical model developed by Ernst in 1971. The transient state solution of this model is developed applying the Laplace transform, and it is verified against the finite-difference solution. Examining drawdown and total storage change reveals the relations between the presented one-dimensional radial flow solutions. The assumptions underlying these solutions are discussed in detail to show their limitations and to refute misunderstandings about their applicability. The discussed analytical models and the formulas derived from it to estimate the radius of influence cannot be regarded as substitutes for advanced modeling, although they offer valuable insights on relevant parameter combinations.

Groundwater Modelling and the Scientific Method: Part 1 и Part 2. Очень интересные рассуждения в формате видеолекции о смыслах и методах гидрогеологического моделирования, сложностях калибровки и достоверности прогнозов. Состоит из двух частей: первая больше философская, а во второй рассматриваются реальные примеры.

This first video begins by examining the scientific method. It then examines the way in which decision-support groundwater modelling is commonly undertaken. It demonstrates that differences between the two are profound. It then shows how groundwater modelling can actually be aligned with the scientific method. Once this happens, it can support groundwater management much better than it presently does. It can also reduce the cost of groundwater model construction and deployment, while increasing returns on investment in groundwater data.