surface water

Bogota's wetland distribution（Publicado，2022）

Overview: Bogota is situated in a high-altitude basin. The city and surrounding land are primarily distributed along sub-basins, including: Río Torca (Torca-Guaymaral), Río Salitre (also known as the Juan Amarillo River), Río Fucha, and Río Tunjuelo. These sub-basins contain a complex network of waterways, including streams/tributaries, rivers, wetlands, canals, and artificial waterways—approximately 200 water bodies in total—spread throughout the city and suburbs, ultimately flowing into the Bogota River. “The Bogota River basin is composed of a natural system formed by ravines, rivers, lagoons, and wetlands, most of which are tributaries of the Bogota River, plus a regulation system consisting of nine reservoirs and an irrigation district.” (Díaz-Casallas, Castro-Fernández,Bocos, Montenegro-Marin, Crespo, 2019)

Framework: “The POMCA defines the basin as a hydrological unit for comprehensive planning and management of water resources, integrating rivers, tributaries, wetlands, and water use regulation.” (CAR, 2019) The Bogota River is the main river in the basin, and it has three tributaries: Salitre, Fucha, and Tunjuelo, which are the main carriers of urban drainage systems and mountain runoff. Although the wetlands of Bogota are not a major component of surface water, they are key nodes in the surface water system, playing a major role in filtering pollution and mitigating soil erosion. Today, as the rarest highland wetlands, Bogota still has 15-17 wetlands according to various institutions. Due to historical reasons, five hundred years ago, when Bogota was still a plain, the Muiscas indigenous group had already utilized wetlands to improve drainage. ‘Although the region surrounding Bogotá was, according to Rodríguez, “a highly floodable plain with difficult [natural] drainage,” Indigenous groups developed and operated a sophisticated system that used the region’s floods to their advantage.’ (Garzón & Flórez, 2022)

Connection: (1) Rainfall—Bogota lacks large-scale snowmelt and lake supply; the main source of surface water is rainfall. Due to the unique characteristics of the Bogota region, annual rainfall is extremely uneven, with heavy rainfall concentrated in April-May and September-November. Each heavy rainfall will increase surface runoff, posing a risk of flooding. (2) Tunjuelo River—It is a tributary of the Bogota River and is part of surface water. This tributary is also the most polluted by humans. Solid waste dumping and mining have resulted in high turbidity and high sediment content in this tributary, which is listed as a low-quality section in the WQI. (3) Quebrada Limas—Mountain streams are an important surface water supply system, transporting the water brought by rainfall from the mountainous terrain to the Bogota River. (4) Groundwater—It has a strong correlation with the surface water wetland system mentioned above. During the rainy season, wetlands replenish groundwater; while during the dry season, groundwater replenishes wetlands. The pollution of these two is also interconnected. (5) Waste Management / Landfill Leachate – For the largest landfill, Doña Juana Landfill, its leachate has the potential to enter the Tunjuelo River. This leachate entering the river can lead to high levels of COD, NH₄⁺, and heavy metals, and is identified as a “key environmental risk” in the POMCA literature.

Reference Garzon,C. and Florez,S.(2021)' Aerial Photographs Uncover Bogotá’s Indigenous Hydraulic System'Available at:https://eos.org/articles/aerial-photographs-uncover-bogotas-indigenous-hydraulic-system

Díaz-Casallas,D., Castro-Fernández,M.,Bocos,E., Montenegro-Marin,C., Crespo,R.(2019)'2008–2017 Bogota River Water Quality Assessment Based on the Water Quality Index'Available at:https://www.mdpi.com/2071-1050/11/6/1668

EJECUTIVO，R.(2006)'PLAN DE ORDENACIÓN Y MANEJO DE LA CUENCA HIDROGRÁFICA DEL RÍO BOGOTÁ' Available at:https://repositorio.gestiondelriesgo.gov.co:8443/bitstream/handle/20.500.11762/22595/11-1-POMCA-RIO-BOGOTA.pdf?sequence=1&isAllowed=y