Revision as of 14:35, 11 November 2021

Plugin folder Kalypso-NA 4.0

Description of new functions

In order to answer current questions in research, the computational core Kalypso-NA (from version 4.0.0.) has been revised in the years 2016 - 2020 with additional functions. The following functions have been implemented:

SUDS detailed simulations of the hydrological processes

The hydrological processes are computed in more detail by additional parameter sets of the soil and drainage structures of SUDS. Using the example of laboratory tests on green roofs, a detailed examination and verification were carried out.

Implementation of a dynamic simulation time step (short term simulation runs).

The infiltration into porous materials is simulated with a dynamic time step. If there is a large amount of inflow onto a small area (e.g. swale filter drain systems), the time step is reduced.

Backwater effect between layers

When the maximum storage capacity is reached in a storage layer, the water is restowed into the layer above of it. However, the overflowing water can also be discharged to a user-defined target. If the overflow of the uppermost soil (storage) layer occurs, the water is drained to the outlet node of the overlay or of the subcatchment. If a flow path and flood routing parameters have been defined, a flood routing of the overflow volume is calculated. The target of the overflowing water can be other overlay areas or a node. Details are explained in the publications (Hellmers, 2020) and (Hellmers & Fröhle 2017).

Coupling of different SUDS

If there is an overflow of water in a storage layer, this overflow can be drained in a controlled manner to other layers of the same or other SUDS (overlay types). This makes it possible to simulate cascading drainage systems. Details are explained in the publications (Hellmers, 2020) and (Hellmers & Fröhle 2017).

Flood routing calculation in river profiles using geometrical forms

Simplified geometric shapes serve as input profiles (trapeze, circle) in order to calculate the Kalinin-Milyukov parameters k,n. The friction parameters can be calculated with the methods of Darcy-Weissbach or Manning-Strickler. The user selects the calculation method.

Flood routing calculation among SUDS

The position of SUDS can be defined by specifying the X, Y, Z coordinates. As a result, the flow path length between SUDS is automatically calculated and optionally adjusted by an extension factor. However, the modeler can also specify a fixed flow path length. The flood routing calculation is done using the previously mentioned flood routing method.

Control functions of structures in water streams

Control functions for hydraulic structures in water bodies have been implemented. Closure, opening and 3 different outflows from the constructions are activated when threshold values are reached within precipitation, discharge or water level time series. This allows the simulation of tide gates, locks, weirs, etc. (see NA model Dove-Elbe). Details are explained in the publications (Hellmers, 2020) and (Hellmers & Fröhle 2020).

Control functions for retention layers (e.g. cisterns, retention roofs)

Within SUDS retention layers are present in different SUDS types. Here, water is retained or drained in accordance with the use of rainwater (e.g. cisterns: rainwater harvesting) and in accordance with the rain forecast (e.g. retention roof).

Backwater effect in water streams

Especially in open water streams with shallow water tendencies (e.g. marsh lands), the closing/opening of hydraulic structures causes a backwater effect in front of the structures. This leads to an afflux of the water volume and the water level rises. The calculation of water levels and the recalculation of the water volume into the upper streams is done by additional functions in the calculation core and additional parameter sets in the plugin folder Kalypso-NA (Kalypso-NA version > 4.0.0). Details are explained in the publications (Hellmers, 2020) and (Hellmers & Fröhle 2020).

Publications

Hellmers, S. and Fröhle, P. (2021)

Computation of backwater effects in surface waters of tidal lowland catchments including control structures – An efficient and re-usable method implemented in the hydrological open source model Kalypso-NA (4.0), Geosci. Model Dev. Discuss. [preprint], https://doi.org/10.5194/gmd-2021-140, in review, 2021.

Hellmers, S. (2020)

Integrating local scale drainage measures in meso scale hydrological modelling of backwater affected catchments [TUHH Universitätsbibliothek]. https://doi.org/10.15480/882.2627

Hellmers, S. and Fröhle, P. 2017

Integrating Local Scale Drainage Measures in Meso Scale Catchment Modelling. Water 9, no. 2: 71. 2017 https://doi.org/10.3390/w9020071