Proposals for Lake Titicaca restoration

Using Ecological Engineering to restore Lake Titicaca

Prepared by Xavier Lazzaro (BOREA/IRD)

We can observe the limits (tecnical, logisitic, financial) of classical sanitation based on Wastewater Treatment Plants (WWTP). The clear example is the only Puchukollo WWTP landlocked into the city of El Alto, undersized with a capacity of 400,000 inbitants in the face of a population of > 1 million inhabitants, an outdated technology of just primary-level treatment, resulting in a contamination source into the Seco river, an affluent of the Katari river which opens into Cohana bay and Lago Menor. Thus, it is urgent to consider technologies based on nature, i.e. the principles of ecological engineering, that are beneficial to both the environment and the society. At such large scale, it is not an alternative but a complementary approach. More details can be found in the 4th Chapter of our book 'Observatorio permamente del Lago Titicaca' (see pdf link in the Bibliography section of this webpage). 

Definitions of Ecological Engineering or Ecotechnology

Prof. Howard T. Odum was the first to define ecological engineering as "the manipulation of the environment by man using small amounts of supplemental energy to control systems in which the main energy impulses continue to come from natural sources" (Odum 1962, Odum et al. 1963). He later defined this concept as "the management of nature is ecological engineering.... a partnership with nature is a better term..." (Odum 1971), and "...the engineering of new ecosystem designs is a field that utilizes systems that self-organize..." (Odum 1983).

Prof. William J. Mitsch significantly boosted the discipline by: 1) developing the field of ecological engineering as the author of the first book on the subject (Mitsch & Jørgensen 1989) and founder in 1992 and editor-in-chief of the scientific journal Ecological Engineering; 2) creating the Olentangy River Wetland Research Park, a unique 20-acre wetland research laboratory, and now Ramsar Wetland of International Importance at The Ohio State University, Columbus, OH; 3) contributing significantly to the development of the field of wetland ecology, notably as first author of five editions of the landmark book 'Wetlands' (Mitsch & Gosselink 2023), which continues to be used worldwide to teach wetland ecology. Mitsch, Eminent Scholar and Director of the Everglades Wetland Research Park, Florida Gulf Coast University, Naples, Florida, has just retired at the end of 2022, after a 47-year career in ecology.

Mitsch (1988) defined 'ecological engineering' and 'ecotechnology' as the "design of human society with its natural environment for the benefit of both". Ecological engineering and ecotechnology offer additional means of dealing with pollution problems by recognizing the self-design properties of natural ecosystems. It is engineering in the sense that it involves the design of the natural environment using quantitative approaches and basing approaches on basic science. It is a technology whose main tool is self-designed ecosystems. The components are all the biological species of the world (sensu Mitsch & Jørgensen 1989).

Uhlmann (1983), Straškraba (1984, 1985), and Straškraba & Gnauck (1985) defined ecotechnology as "the use of technological means for ecosystem management, based on deep ecological knowledge, in order to minimize the costs of measures and their damage to the environment". Finally, Mitsch & Jørgensen (1989) considered that "ecological engineering and ecotechnology are synonymous terms".

It should be noted that 'ecological engineering' is not the same as 'environmental engineering', a field developed in universities since the 1960s, formerly called sanitary engineering. Although environmental engineers apply scientific principles, they are taught to use "valuable environmental technologies" such as sedimentation tanks, scrubbers, sand filters and flocculation tanks. In contrast, ecological engineering is concerned with identifying the ecosystems most adaptable to human needs and recognizing the multiple values of these systems. Ecological engineering is about designing human society in harmony with its natural world, rather than trying to conquer it. Nor should it be confused with bioengineering and biotechnology. Bioingineering involves the manipulation of the genetic structure of cells to produce varieties and organisms capable of performing certain functions. Biotechnology involves manipulations at the micro-level of cells, which generates enormous costs and concerns. Ecotechnology, on the other hand, does not try to introduce new species that nature has not faced before, avoiding invasion by exotic species.

Ecotechnological methods can be used to solve environmental problems, such as for example:

Eutrophication: Ecotechnology intervenes through an artificial wetland created to trap nutrients in the inflow, and/or nutrient-rich hypolimnetic (= at the bottom) waters are siphoned downstream from the lake.

Sludge disposal: The eco-technological solution recognizes sludge as a resource of nutrients and organic matter, and deposits it on agricultural land, where the resource can be utilized.

Drinking water treatment: The ecotechnological method uses an artificial wetland designed to be a self-sufficient system with surface vegetation production that provides organic matter for denitrification to take place.

Fish farming: In integrated fish farming, herbivorous fish consume the algae, while detritivorous fish use the detritus and serve as food for other fish, thus eliminating pollution.

Feasible ecotechnological strategies to control the eutrophication of Titicaca Lago Menor 

Eutrophication and pollution have been recurrent problems in the Internal Bay of Puno (BIP) since the 1970s due to untreated wastewater discharges from the city of Puno (see references in Northcote et al. 1991), worsened by the collapse of the Espinar WWTP. Meanwhile, for the Bolivian sector of Lago Menor, it was necessary to wait for the pioneering work of Fonturbel in the 2000s. In Cohana Bay, polluted by wastewater from the growing city of El Alto, Fonturbel (2005) used chemical (pH, turbidity, TN, SRP, BOD5) and biological (thermotolerant coliforms) indicators. In 3 areas of 100 m2, he sampled floating (Lemna) and submerged (Myriophyllum; he did not find Chara) macrophytes to measure coverage and diversity. He collected phytoplankton of size ≥ 25 µm (filtered in a net) dominated by cyanobacteria Gomphosphaeria, and green algae Closterium and Mougeotia), with lower diversity. Unfortunately, this procedure omits the most abundant microphytoplankton, e.g., the green alga Carteria sp. < 10 µm responsible for the 2015 Bloom. He relied mainly on surface proliferation of Lemna, relative reduction of cover in Totora and Chara, increased turbidity, excess nutrients and organic matter, reduced dissolved oxygen, to demonstrate the rapid advance of eutrophication.

According to the maximum permissible limits of Bolivian legislation (Annex A of the Water Pollution Regulations of Environmental Law 1333), it classified Cohana bay as Class D (minimum quality, not suitable for human use). Since then, he recommended taking urgent mitigation measures and implementing a comprehensive Environmental Monitoring Plan. Based on his Master's research, Fonturbel published a book (Fonturbel 2008) on cultural (anthropic) contamination. He highlighted perspectives by taking up his proposals to remove excess nutrients from eutrophicated waters through bioreactors and biodigesters using aerobic and anaerobic microorganisms, photobioreactors with photosynthetic microorganisms, as well as phytoremediation technologies, which do not require the construction of costly infrastructures (WWTPs), both of which are environmentally friendly. Two decades passed, pollution and eutrophication in the Katarí basin and the littoral of Lago Menor increased, without additional functional WWTPs (in addition to Puchukollo), nor environmentally friendly technologies (above). Decades are passing without intervention. As a result, the costs of remediating the deteriorating waters rise until they will become technically unfeasible. In the meantime, the health and sanitary conditions of the populations only degrade.

Proposals to reduce pollution from El Alto-Viacha to Lago Menor

To curb eutrophication in the littoral and pelagic zones of Lago Menor, it is essential and urgent to control point and diffuse discharges of nutrients and organic matter from human waste in urban areas upstream, and from agricultural activities downstream of the watersheds (Katari, Sehuenca, Batallas), respectively. Conventional WWTPs contribute to the treatment of domestic wastewater, but not all wastewater. The treatment of industrial pollution requires specific WWTPs that are not contemplated in the Katari Basin Master Plan (MMAyA 2018), which only includes the expansion of the Puchukollo WWTP, which captures ≤ 60% of the municipal wastewater from the city of El Alto. This project was abandoned by the selected concessionaire company.

The purpose of this section is not to implement a complete project with evaluation of financial costs as well as environmental and socioecological benefits. Rather, it is a brainstorming exercise on how to combine the ecological paradigms with some technological advances in treatment 'mini-plants', or 'compact plants', to reduce the load of nutrients and organic matter discharged from the Katari watershed to Lago Menor. The hydrological peculiarities and the dispersed population of the Altiplano have to be taken into account, which do not allow the conventional use of large WWTPs. These compact treatment plants could be operated as community plants close to river courses or even at the district level in the city.

Innovation 1: Using Compact Wastewater Treatment Units

A 'Waste Water Treatment Plant' (WWTP) has generally two very distinct functions. The first is to treat wastewater by removing pollutants before returning it to nature. The second is to make natural water clean and safe for human consumption. The Puchukollo WWTP, as well as the other WWTPs planned for the Katari watershed, do not have the second mission. A WWTP removes pollutants from the water through four processes: (i) mechanical treatment that removes waste by screening and decanting; (ii) biological treatment that removes organic and mineral matter by microbial culture; (iii) chemical treatment that removes hazardous substances by adding chemicals; and (iv) disinfection by ultraviolet (UV), ozonation (O3) or chlorine (Cl), which removes pathogenic germs.

Classical WWTPs are not suitable for rural areas because it is unfeasible to connect dispersed households that are several kilometers away, as is the case in the Altiplano, and in the lower part of the Katari watershed. Therefore, other smaller scale and less expensive alternatives must be sought. In contrast, compact-WWTPs are small and mobile. These are transportable units the size of a 20 or 40-foot maritime containers. They occupy a small footprint on the ground. They do not require settling tanks. They are not a visual or olfactory nuisance. No need to expropriate land from agricultural landowners. Their acquisition and operating costs are low (≤ million dollars). They have many advantages: their electricity consumption is low; they can be supplied by solar, wind and/or hydro power. The purification of these compact-WWTPs  is based on different processes, for example: 

(a) The Ultrafiltration (UF) is a separation process that uses screening as the separation principle and employs pressure as the driving force to achieve mechanical separation. When the mixed solution containing different sizes of molecular solute flows across the membrane surface, the solvent and small molecules, such as inorganic salts, pass through the membrane and the macromolecular solute is trapped to achieve the separation and purification goal. For example, HINADA Water Treatment Tech CO LTD[ https://www.hinada.com/product/200m3-day-mobile-wastewater-stp/] (China) produces a mobile unit (2.3 x 2.5 x 11.5 m) capable of treating 200 m3/day of wastewater, with output water that meets international standards for discharge and reuse in irrigation, and an electrical consumption of 10 kW/h. It has (a) an anaerobic tank, (b) an aerobic tank, both with 30 m2 of biological filters (membrane bioreactor or MBR), (c) an MBR tank with 10 m2 of membrane filters (0.05 µm pore size), (d) a 2 m3 clean water tank, (e) several pumps and aeration system, and (f) an automatic control system with PC and touch screen.

(b) The combination of sedimentation, microfiltration, ultrafiltration and UV sterilization to remove visible particles from the water as well as bacteria, viruses and many other substances potentially hazardous to health. For example, IDRO GROUP[ https://www.idro.net/upload/blocchi/BLUE_ULTRA-Idrogroup-EN.pdf] (Italy) produces a mobile BLUE ULTRA unit (0.8 x 0.8 x 1.2 m) capable of purifying water (from sources such as rivers, lakes, dams, rainwater reservoirs and wells) microbiologically and chemically deteriorated for the production of drinking water (0.5 to 2 m3/hour), with low energy consumption (1 to 1.5 kW/h) ideal for use with alternative energy sources, such as solar and wind power. 

(c) The filtration with sand, activated carbon and disinfection that removes solid particles and organic compounds. For example, IDRO GROUP (Italy) also produces a mobile BLUE TWINS unit for the production of drinking water free of physical and bacteriological contamination, from wastewater free of industrial pollutants, hydrocarbons and chemical residues. The unit is installed on a small trailer (0.8 x 1.6 x 0.9 m, 750 kg). It operates without electricity. Only the suction pump needs to be powered by a diesel pump, or a solar powered pump. It has a capacity of 4 m3/hour. It has two flexible compartments for the storage of drinking water.

(d) The biological treatment with several complementary technologies. For example, FILTOMAT WATER SYSTEMS[ https://www.f-w-s.com/sistemas-tratamiento/planta-efluentes/contenedor-efluentes-industriales.html] (Argentina) produces a containerized unit for the treatment of industrial and sewage effluents from small communities to provide safe water for irrigation and other uses. It integrates solid-liquid separation, clarification, sludge concentrate, tertiary effluent filtration treatment and disinfection for water reuse.

(e) The Advanced Oxygenation with  ozonation and ultraviolet light. Called OXIPLUS™, it is internationally patented by DELLEPERE ENTERPRISES[ http://www.dellepere-ent.com/dellepere/la-tecnologia/] (USA). It consists of an injection of oxygen (O2) and ozone (O3) in the form of microbubbles in conjunction with UV light. This dosing drastically reduces the biological and chemical oxygen demand of the water, the phytoplankton microalgae biomass in particular cyanobacteria, the content of total and fecal coliforms, heavy metals, improves turbidity, color and reduces odors produced by undesirable anaerobic situations. DELLEPERE ENTERPRISES produces two types of plants with the OXIPLUS™ system: (a) A vessel, the Scavenger Vessel™ (12 x 2.5 m, draught 1.4 m, 5 t) which also collects floating waste, injects about 150 m3 of O2/hour at a depth of 9 m and decontaminates between 38 and 76 m3 of water/min. It is planned to use two Scavenger Vessel™ to reduce eutrophication in the inner bay of Puno, through an ALT program. Yet, it is unsuitable for use in the littoral zone of Lago Menor and Bahia Cohana (depth ≤ 1 m) because it is too wide and deep to circulate in the channels within the totora. (b) A floating Stationary Plant (4.3 x 2.1 x 2.5 m, 1.3 t) that generates an aeration of up to 120 mg O3/hour together with oxygen by means of surface microbubbles, with a capacity of 90 to 260 kg/hour up to a depth of 3.5 m. It can be transported in a 20 feet sea container. Due to its dimensions and characteristics, it is suitable to be anchored at the mouths of rivers in the Lago Menor, e.g. in the Cumana and Cohana bays. 

(f) The Supercritical Water Oxidation (SCWO) is opening a new era in sustainable waste management. It can be classified as 'green chemistry' or 'clean technology'. It is a physical-thermal process fueled by water above its critical point (374°C and 221 bar) and air that produces a highly efficient oxidation reaction that completely removes organic compounds into carbon dioxide, nitrogen gas, clean water and mineral salts. The reaction generates energy and safe products that can be recovered and reused. The heat from the oxidation reaction is used to heat the influent stream; excess heat is converted to electricity. 

Innovation 2: Separating wastewater and stormwater, and combining constructed wetlands with compact treatment units

In view of the inertia in the connection, construction and commissioning of urban WWTPs and in the face of climatic and demographic pressures, it is urgent to become innovative by combining ecological engineering and state-of-the-art sanitation technology, such as: (a) Separating wastewater and stormwater in urban areas; (b) Prohibiting (controlling) and eliminating all point and diffuse discharges of wastewater into rivers and the lake. (b) Prohibiting (controlling) and eliminating all point and diffuse discharges of wastewater into rivers and the lake. (c) Concentrating all sources of wastewater into pipes running along rivers; using circulating pumps; incorporating local sources of wastewater and treating them with compact plants. (d) By exclusively transporting snowmelt and rainwater, the rivers will quickly recover, becoming transparent and once again harboring plant and animal life, noticeable to riparians. (e) Feed two compact treatment units (evaluate the best options) with the wastewater transported in the pipes; the volume to be treated will be a fraction of the current volume and constant throughout the year; because of their compact sizes there will be no need to expropriate land; there will be no visual or olfactory nuisance either. (f) In the delta of the Katari, Sehuenca and Batallas rivers, construct artificial wetlands in flood zones, i.e. replant cattail, dig shallow earthen basins inoculated with cattail, Chara, Lemna, Azola, implement floating islands of cattail in rivers (as practiced in China), both to increase natural biological filtration of nutrients, organic matter and pollutants. (g) At river mouths (not in the lake per se), deploy stationary OXYPLUS™ plants, injecting O2, O3 and UV, to remove undesirable microalgae, bacteria, and coliforms. Two plants could be moved between 4 river mouths, and these measures could be applied at the mouths of the Tiwanaku and Guaqui rivers. (h) Use dry latrines in homes, take garbage (plastics) to recycling centers. (i) Promote and strengthen environmental education in educational institutions and in the professional environment of El Alto, Viacha and other municipalities that are the main generators of pollution into Lake Titicaca. (j) If environmental awareness is not created, the population will continue to be indifferent and ignorant of the fragile situation of the lake and the affected communities. 

Innovation 3: Promoting ecological engineering based on phyto-remediation, using constructed wetlands (CW) 

Lake eutrophication is a huge global environmental challenge (Carpenter et al. 1998, Smith 2003). The control of external nutrient loading from the watershed is considered to be one of the most difficult problems to achieve acceptable water quality. Technological solutions, such as the sophisticated tertiary treatment by WWTPs, as well as other technological solutions for diffuse sources from urban, industrial and agricultural activities, are very expensive, and ultimately result inefficient. 

Increased aquatic macrophytes can contribute to nutrient removal and improve water quality in shallow lakes. Several macrophytes have been successfully used, in particular various types of sedges, or emergent macrophytes such as Phragmites australis, Typha spp. and Scirpus spp. (cattails) (Wu et al. 2011). Through direct absorption, and indirect absorption via the periphyton (i.e., the biofilm of mycoralgae and bacteria) covering the stems, and denitirification by the rhizosphere (i.e., the region of sediment directly formed and influenced by roots and plant-associated microorganisms (bacteria)), macrophytes convert nutrients into organic compounds, removing them from lakes. At the same time, they increase evapotranspiration (by up to 3-10 times, Borin et al. 2011), which reduces water volume, and in turn decreases its quality. Then, a rational control of macrophytes by planting and also harvesting is very important (Xu et al. 2014). 

The results of Mazzeo et al. (2003) in Uruguay could serve as a model to better understand the ecological functioning of Lago Menor. Lago Blanco has an extensive cover of Egeria densa (i.e., an Elodea of the family Hydrocaritacea), an invasive cosmopolitan submergent macrophyte of spatial structure close to Chara, with a fish community restricted to two small omnivorous-planktivorous fishes. The most important differences in phytoplankton biomass found between areas with and without macrophytes coincided with a high biomass of herbivorous zooplankton and/or macrophytes occupying the entire water column during the low level period. Nutrient removal mechanisms by E. densa also contributed to maintaining clear water. The same sequence of mechanisms could apply to Lago Menor. In nutrient addition trials, Egeria suppressed phytoplankton, which suggests that they control phytoplankton by allelopathy (i.e., a biological phenomenon in which an organism generates biochemical compounds that benefically or detrimentally influence the survival, growth o reproduction of other organims). This mechanism could also occur in Lago Menor, as Chara also can even control the bloom-forming phytoplankton through allelopathy (Zloch et al. 2018). 

Artificial (or constructed) wetlands not only complement and operate with a cost lower than that of classical WWTPs, but they perform respectful of the environment. Natural wetlands have been used during centuries to treat wastewaters, preliminarily to eliminate them instead of treat them. Those wetlands served as an easy receptacle. Discharging wastewaters in uncontrolled manner provoked the destruction of numerous wetlands worldwide. Using natural wetlands for such treatment although under controlled conditions lasted until the 1980s, especially in the USA. They were difficil to maintain and the treatment efficiency was quite unpredictable. Thus, they were replaced by constructed wetlands, carefully designed (Mitsch & Gosslink 2000). The direct role of macrophytes is removing nutrients and contaminants; for this they have to be harvested. Its indirect role is much wider, such as supplying oxygen to anoxic environments, providing substrates to attached bacteria, excreting anti-bacterial compounds, as well as reducing the wind influence so allowing the sedimentation of suspended solids, and consequently increasing water transparency. 

Fonder & Headley (2010) classified constructed wetlands (or CW) into two large groups: a) 'surface flow CW' or 'free water surface' CWFS; and b) 'sub-superficial flow CW' or 'sub-surface flow' CWFSS. They can be classified according to the types of macrophytes: a) free-floating macrophytes; b) macrophytes with floating leaves; c) submerged macrophytes; d) emergent macrophytes; and e) trees. The first constructed wetland documented for wastewaters treatment was patented in 1901. In the 1980-190 decades, the use of constructed wetlands for wastewaters treatment expanded rapidely to the whole world. By the end of the 1980', Germany published the national guidelines regarding the design and functioning of constructed wetlands for the treatment of wastewaters, and sooner after the European guidelines were published. In Northern America, the CWFS were regularly constructed during the 1980'. Many of these systems were used as tertiary treatment units of municipal wastewaters in large areas. In South America, the CW were only applied in Brazil. Research were focused on water hyacinth (Eichornia crassipes) in combination with vertical CW with ascendant flux, named 'filtering soil'. 

During 1990', CW technology extended to all continents. In 2000, CW became a 'certified' method for treating wastewaters in most countries. In some countries, such as China, the number of CW overcomes the he hundred thousand. It is also increasing in South America, especially in Colombia, Argentina and Chile. CW are efficiently used in cities to treat wastewaters, grey waters (i.e., the relatively clean waste water from baths, sinks, washing machines, and other kitchen appliances), stormwater overflows and runoffs, for recycling water within cities, and form part of sustainable urban drainage systems (or SUDS).  

CW for treating agricultural contamination - Li et al. (2021) rewieved the substrates and macrophytes species optimum foe CW for proceeding nutrients from agricultural runoffs, because they generate phytoplankton blooms (i.e., microalgae proliferation), contaminate environments, disturb fishing and tourism activities, and threaten water security. They identified three most adecuate substrates: gravel, zeolite, and slag. However, according to raw material availability, it can be used: bentonite, slate, sand, husk, rice straw, fly ash, hollow brick pieces, and slag. Between emergent macrophytes, the most optimum are Eleocharis dulcis, Typha orientalis y Scirpus validus; the submerged Hydrilla verticillata, Ceratophyllum demersum y Vallisneria natans; the floating Eichornia crassipes and Lemna minor; and of floating leaves Nymphaea tetragona y Trapa bispinosa. Yet, meteorological conditions and seasonality, hydrology, and climate change are important to consider for their effects on contamination by nutrients diffusion; as well as, the competitive effects between macrophytes species and interactions between plants and substrates. 

CW with emergent macrophytes - They are the most used in CW with (sub)-superficial fluxes. However, they do not tolerate large water level fluctuations. Wu et al. (2011) assessed the long term performance of N and P elimination between four species of emergent macrophytes: Typha orientalis, Phragmites australis, Scirpus validus, and Iris pseudacorus. The plants grew well with a high remotion capacity of nutrients, greater in Summer, and maximum for S. validus and I. pseudacorus, the preferred species in CW for the wastewaters treatment in Northern China. 

CW with emergent floating macrophytes (FTWs) - These are emergent plants that grow artificially in a a blanket that floats at the water surface, instead of being rooted in the bottom sediment. Those FTWs are frequently used in rainwater tanks because they are able to tolerate their typically large water level fluctuations. Tanner & Headley (2011) experimented four emergent species of macrophytes using floating blankets: Carex virgata, Cyperus ustulatus, Juncus edgariae, and Schoenoplectus tabernaemontani (sedge family or bulrush) to eliminate dissolved phosphorus and fine suspended solids, turbidity, plus copper and zinc. The release of bioactive compounds from the plant roots, or the cahnge in physical-chemical conditions in the water column and/or in the soil of the planted FTWs improved indirectly the elimination process through the modificstion of the metal speciation (e.g., stimulating the complexation or flocculation of dissolved fractions, and/or the sorption characteristics of the biofilms. The research team of Achá (2022) implemented a similar study, within their PNUD 03-B-03 BIOREM pilot project. Initially planned for the Huatajata and Cohana bay, in Lago Menor, due to pandemia, the experiments dedicated to assess the remotion capacity of nutrients, and consequently the reduction in chlorophyll-a concentration of phytoplankton, by floating emergent totoras (Schoenoplectus californicus spp.) were conducted in 2.5-m3 mesocosms in the UMSA Campus in Cota Cota, La Paz southern zone. The measured remotion rates were consistent with those of Tanner & Headley's (2011), although in a diferent climate context. However, the huge potential of a floating wetland with Totora exceeds several times the need for contaminants remotion measured in the natural environment. 

CW with sumerged macrophytes - The communities of submerged macrophytes present mechanisms for eliminating phosphorus (P) that are not encountered in wetlands dominated by emergent macrophytes. These include the direct assimilation of P in the water colum from part of the plants, and the co-precipitation of P with calcium carbonate (CaCO3) mediated by pH (Dierberg et al. 2002). This phenomena can be observed in shallow areas (≤ 2 m) in Lago Menor. It materializes as fine white sand areas of few meters in diameter, within a Chara sp. meadow. Indeed, incrustations of CaCO3 (skeleton) represent 59-76% of Charophytes dry weight (Pelechaty et al. 2013). Thus, submerged macrophytes could be used to increase the performance of CW in P remotion. 

Conclusions for Lago Menor - Two decades have passed. Contamination and eutrophication have been magnified in the Katari watershed and Lago Menor littoral, without counting on either compact WWTPs (addtional to Puchukollo) or environment friendly CWs. Without such interventions, the costs of remedying the water deterioration are just increasing until they will become technically non-viable. Meanwhile, the sanitary conditions  and the population health are just degrading. 

Perspectives: Our responsibility towards future generations

The growing pollution of the rivers of the Katari basin caused by the lack of control of discharges from urban areas, increases the eutrophication of the littoral and pelagic zones of Lago Menor, and the risk of bloom accompanied by mortality of aquatic organisms. In the next decade, it is to be feared that, if immediate protection and restoration measures are not taken, the poor quality of the lake's water will make it impossible to use, given the technology required to treat it and its high cost.

These risks, and their socio-economic consequences, are disastrous for the local populations, including the urban ones which will soon be the most affected. It demonstrates that the irrational growth of urbanization will not be able to continue with its depredation of the environment (agricultural lands, groundwaters) and natural resources, ignoring the devastating effects on the ecosystems, as well as on the living conditions and productions of the downstream populations. An urban-rural solidarity of the civil society is required, together with the awareness of responsibility of the authorities of the urban areas, in the dramatic affectation of the environmental quality of the rivers and the Lake. Basic sanitation has to become an effective priority. Given the scale of the challenges, in relation to the limited resources of rural municipalities and the level of regional poverty, only a National Program for the Protection of Lake Titicaca and its watershed will have sufficient resources to significantly reverse this situation. This requires a firm decision and political commitment from the Bolivian government. 

It is unacceptable to continue observing the irreversible deterioration of Lago Menor caused by the consequences of irresponsible human activities. With this website and our OLT book, we hope to awaken curiosity, passion, and vocations to study it, and to call the political authorities to reflect on the imperative need to implement urgent measures to curb pollution, protect and restore this irreplaceable and unsurpassable body of water for the transbounday region and the world. A solid knowledge of the functioning of Lake Titicaca and its responses to disturbances, together with education about nature, are essential for this success!

Closing remarks: Only together, with responsible attitudes, will we be able to restore the grandeur, integrity and attractiveness of Lake Titicaca so that future generations can continue to enjoy it!