The lake is endorheic, or a closed lake system in which evaporation approximately equals inflow and its water level is controlled primarily by evaporation. However, the level of Lake Managua raises significantly during periods of heavy rain.
At one time, the lake was drained by the Tipitapa River, which flows into Lake Nicaragua. However, it ceased to function as a regular outflow by and now serves as only an occasional overflow mechanism. The level of Lake Managua raises significantly during the periods of heavy rain. The highest water level was recorded during the flooding of The lake rose 3 m 10 ft in five days during Hurricane Mitch in , destroying the homes of many who lived on its edge.
Since then, the city has prohibited residential use of the most flood-prone areas: those with an elevation below Lake Managua has been described by some as the most contaminated lake in Central America.
From a technological standpoint, the trickling filter treatment system was a novelty in Central America. It requires comparatively simple machinery and offers a relatively high purification capacity at relatively low operating and maintenance costs. The project also pursues an integrated approach: within the scope of ongoing supplementary measures, the biogas produced during sewage sludge treatment is used to supply energy to the plant and the treated sewage sludge is dried and used as fertiliser in agriculture.
As part of its approval as a fertiliser for the Nicaraguan market, ENACAL has also conducted tests at a test site to determine the effectiveness of the fertiliser on the growth of various plant species. Since the plant is now reaching the limits of its capacity after ten years of operation, a follow-up programme to increase the treatment capacity is currently being prepared.
The programme aims to connect additional households in Managua to the wastewater treatment plant and to properly treat wastewater from the two neighbouring towns of Tipitapa and Ciudad Sandino, which was still discharged untreated into the lake. This will not only safeguard what has already been achieved in terms of a cleaner Lake Managua, but will also further improve the water quality of the lake.
KfW Development Bank. Skip to main content. Freezing period: None. Mixing type: Polymictic. Notes on water mixing and thermocline formation The lake water overturns at least once a day even on calm days and mixing frequency increases when wind force grows. Dry season April May : 0. Dry season April May : 9. Dry season April May : 1. Cladocera Diaphanosoma fluviatile, Moina micrura , Copepoda Arctodiaptomus dorsalis, Thermocyclops inversus, Mesocyclops nicaraguensis, M.
Fish Cichlasoma rostratum, C. NAM Photosynthetic activity during three different days [mg O2 m-2 day 1] 6. NAM Seasonal variations of total phytoplankton biomass, dominant species and the proportions of biomass belonging to different taxonomic groups 4.
NAM Temporal changes of phytoplankton abundance in the two basins in terms of a chlorophyll a and b fresh weight biomass 4. NAM Fig. NAM Temporal changes of zooplankton mean density and monthly rainfall 5. NAM Estimated and observed mercury levels by the industrial discharge 1. Total mercury concentration 8 In water [micro l-1], Sampling site Jan Apr 1 2 0.
Hg min. T-P:
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