Water and Memory in Melipilla

The relationship between memory and water in Melipilla is fundamental to understanding its identity. The city, located in a fertile valley, filled with vegetation and agriculture, is vital for having plenty of water. Melipilla has a river and a stream, the Maipo River and the Puangue Stream, important for agriculture and vegetation, as Melipilla is linked to its agricultural tradition. The irrigation canals and irrigation ditches, many of them centuries old, are a physical reminder of the efforts of generations to master the land and transform it into a productive and community-based area.

Purpose of rivers: The purpose of rivers in Melipilla is primarily related to water resource management and the protection of riparian ecosystems, given that they perform key functions such as providing food, regulating water temperature, retaining pollutants, and transporting nutrients to the soil.

Functions of rivers: Rivers, as natural waterways, perform fundamental ecological and cultural functions. They transport water and solid materials, form diverse ecosystems that harbor multiple plant and animal species, and act as ecological corridors connecting landscapes. They also possess high aesthetic, symbolic, and recreational value, and are key elements in shaping the natural and cultural heritage of societies.

River food regime:  The rivers in Melipilla, as in other regions, are fed by diverse sources, such as pluvial, nival, and mixed sources, which include rainfall, glacial melting, snow, and other sources. These combined processes ensure the flow and availability of water in Melipilla's rivers, although water quantity and quality can be affected by factors such as human activity, climate change, and land use.

Alfredo, Sánchez Muñoz, Geografía de Chile. Bibliografía Internacional, Santiago, Chile, 2004.

8 POLLUTANTS IN THE MAIPO RIVER: 

Investigations by the Ministry of the Environment have found eight contaminants in the Maipo River water that exceed permitted limits. These include:

Dissolved oxygen (DO): Dissolved oxygen measures the amount of oxygen gas (as O₂) dissolved in water.

Electrical conductivity (EC): A measure of the ability of aqueous solutions to conduct electrical current.

pH: pH is a measure of the acidity or alkalinity of water. It is defined as the concentration of hydrogen ions in water.

Chloride (Cl⁻): A compound containing the element chlorine in the form of a chloride ion (Cl-), or a chlorine atom covalently bonded to another molecule.

Sulfate (SO₄²⁻): A mineral or organic salt of sulfuric acid.

Nitrate (NO₃⁻): A salt formed by the combination of nitric acid with a base.

Orthophosphates (PO₄³⁻): Phosphorus-containing salt produced by the hydrolysis of condensed phosphates

Dissolved zinc (Zn²⁺): Zinc in an aqueous solution, where the zinc atoms have separated and are surrounded by water molecules

How is the Maipo basin affected?: Currently, the Maipo River basin is affected by various situations, such as water withdrawals, channel interventions, or discharges, among others. This, combined with climate change, has generated significant changes in the hydrological regimes of waterways and environmental quality.

"Among the various activities that interact in the basin are agriculture, mining, electricity generation, and aggregate extraction, among others, but the pollutant load cannot be attributed solely to them. Other activities are also affected, such as diffuse pollution, which in some cases originates from the community or illegal activities," says Sonia Reyes, Regional Secretary of the Environment of the Republic of the Republic.

Causes of pollution: 

1. Here are some causes of pollution in the Maipo River:

2. Industrial activities.

3. Agricultural activities.

4. Poor waste management.

5. Livestock farming.

6. Mining.

7. Electricity generation.

8. Aggregate extraction.

How does climate change affect the river?

Climate change significantly affects rivers, leading to decreased flow, flooding, droughts, and altered chemical and biological processes in the water.

The reduction in flow is due to decreased precipitation and increased temperature, which disrupts nearby ecosystems (wetlands). It reduces their ability to dilute pollutants, increasing their concentration and currently preventing the river from flowing into the sea.

Droughts and megadroughts are caused by decreased precipitation, melting of glaciers (the main sources of water for the Maipo River), and the prolonged lack of rain. These cause multiple problems for water consumption and transportation, as well as for the flora and fauna of or near the river.

Floods, on the other hand, occur from intense or heavy rains, which can cause mudslides and landslides that increase the river's flow. This causes extensive damage to the surrounding area, necessitating evacuation.

Water situation in Melipilla: Drought is a growing problem in many parts of the world, and Chile is no exception. In recent decades, Chile has faced a significant decrease in water availability due to a combination of climatic, geographic, and human factors.

Melipilla is a province located in the Santiago Metropolitan Region. This area has experienced a considerable reduction in rainfall, leading to a decline in river flows and groundwater levels. Agriculture, a key economic activity in the region, has been particularly impacted by the lack of water, affecting all members of the population, as well as small farmers and large-scale producers.

Most affected sectors: 

The most affected sectors are those experiencing changes, losses, or difficulties due to the river's changes. Whether they are populated or productive/economic sectors, these sectors suffer due to the river's weak channel, drought, pollution, and flooding.

Sectors such as:

1. Engineer Marambio Bridge

2. Agricultural sectors

3. Small-scale family and peasant farming

DIFFERENT SOURCES OF WATER

This map displays the geolocation of rivers such as the Maipo River and estuaries such as the Puangue Estuary, along with various water sales points, where water containers are available for purchase and piped drinking water services are available.

Maipo River

lagoons

water flows

sale of water services

water transportation

estuary

Geolocation:

The Maipo River basin covers three regions: the entire Metropolitan Region, which accounts for 91% of the basin, and parts of the Valparaíso (4%) and O'Higgins (5%) regions. The river flows through the south of Melipilla province, passing along the northern border of the municipalities of Melipilla and San Pedro, and near María Pinto.

Classification of wastewater and wells: 

Wastewater is mainly divided into three categories: stormwater, industrial wastewater and domestic wastewater, which have drainage networks to collect and transport different types of water.

Separative system (method that distinguishes and directs wastewater and stormwater through separate channels to improve treatment and avoid contamination).

Combined water system (method that collects both wastewater and stormwater in a single pipe system)

In our case we will delve into domestic wastewater which is categorized into: black and yellow water.

Wastewater or Sewage: What are they and why are they important in our daily lives? | Water Institute

Black water :Highly contaminated effluents from toilets and sewage systems, rich in organic matter and pathogens.

Yellow waters: Effluents containing mainly urine, with a lower organic load and pathogens than sewage.

Types of wells: To construct a well, technical aspects such as the terrain, the depth of the aquifer, hydrogeological data, and the intended use must be considered. The depth of the well is determined by nearby well logs and tests during drilling and can vary depending on geological conditions and the required flow rate. Wells are classified as:

Dug wells/Norias: These are built for shallow waters. With excavators, they can reach depths of up to 15 meters, and with a barrier, up to 20-30 meters.

Percussion: This technique involves using a hammer or percussion equipment to drill holes in the ground. It is effective for depths of up to 15-20 meters, depending on the hardness of the ground. It is a common technique in soft soils.

Cutting: Also known as "cutting" or "cutting," this is a drilling technique in which a tool is used to abrade the ground material without hammering. It is suitable for depths of up to 15 meters and is useful in less hard ground where percussion drilling is not necessary.

Water injection: This method is used for drilling to greater depths, typically between 30 and 40 meters. Water injection helps cool the drill bit, lubricate the process, and flush debris out of the hole, making drilling in harder ground easier.

Rotary drilling with water injection: This is an advanced method that combines drill bit rotation with water injection. This method allows drilling up to 200 meters and is useful for hard or rocky terrain. The rotation helps cut the material more efficiently, and the water facilitates debris evacuation.

Irrigation techniques through rivers:

One of the main uses of water in Melipilla is irrigation, resulting in techniques such as:

Technologically-engineered macro-irrigation:

An irrigation system composed of highly robust and high-quality machines that fully adapt to the needs and restrictions of the land to be irrigated.

Macro-irrigation with Fixed Cups and Sprinklers:

A sprinkler irrigation system for low-lying, high-volume pastures.

Micro-irrigation:

Uses drip and micro-sprinkler emitters.

Storage ponds:

structures to store water during times of abundance and use it during times of need.

Furrow irrigation: This method is common in the Melipilla region, especially for crops such as corn and alfalfa. It involves running water through ditches or furrows throughout the plot.

Records of droughts and floods: 

Throughout Melipilla's history, we can observe a wide variety of events, including water shortages, floods, droughts, and more, leaving their mark on the community. These events include:

Floods: 

June 22, 2023. Threat of the Maipo River overflowing its banks.

August 23, 2023. Evacuations in sectors of the Melipilla and San Pedro communities.

June 21, 2024. Flooding in the El Rosario sector of María Pinto.

Water crises

January 8, 2022. Water shortage in the province of Melipilla and the municipalities of Curacaví and María Pinto.

August 11, 2020. The municipalities of Curacaví, María Pinto, and Melipilla are declared water shortage zones.

August 21, 2019. Agricultural Emergency Zones due to drought are declared for 17 rural municipalities in the Metropolitan Region.

March 20, 2012. San Pedro de Melipilla, the municipality in the Metropolitan Region experiencing extreme water shortages.

For more information on floods, droughts, emergencies, and historic disasters throughout the country, we invite you to visit the following page from the Ministry of Health and the DES (Health Emergencies Division).

WHAT IS THE STATE DOING ABOUT THE DROUGHT?

State intervention is a key factor in the persistent drought crisis facing Chile. This situation is exacerbated by the state of regulation regarding water use by companies, which are the main consumers of the resource. Although agreements such as the "Blue Certificate" exist, designed to promote more responsible water management, these mechanisms are voluntary. As a result, companies have the ability to divert rivers and watercourses with minimal or no state regulation. This lack of effective oversight contributes significantly to the worsening of the drought in the country.

Water consumption

While the State focuses on reducing water consumption by the civilian population, as illustrated in the posters on the side, reality shows that the agriculture and livestock sectors are responsible for the greatest water consumption and significant water pollution. This discrepancy highlights an urgent need to reorient policies to effectively address the impact of these sectors on water resource management.

Water is a vital resource for the life and sustainable development of any country. In Chile, a country with a diverse geography and varied climatic conditions, water consumption shows trends that reflect both agricultural and urban use. Through this analysis, it seeks to better understand the current water situation in Chile and encourage discussion on the need for conservation policies and sustainable management of this essential resource. 

"More than half of this consumption is taken by the forestry industry, with 384.01 m³/sec (59.16%). It is followed by the agricultural industry 240.17 m³/sec (37%)..... The percentage of human consumption increases to 6.3% if only water from surface and/or underground sources were considered." Consumo de agua en Chile: ¿quiénes gastan más? (theclinic.cl) 

This research paper addresses the drought in San Pedro de Melipilla, analyzing causes, impacts, and possible solutions. Water use in agriculture and daily life is also included, along with interviews with local residents to provide a more comprehensive view of how the drought is affecting the community.

Water crisis in San Pedro de Melipilla, Case study

Next, we'll hear the testimonies of two local farmers from San Pedro de Melipilla, who share their experiences with the drought affecting the region. Through their stories, we'll understand how this crisis has impacted their crops, their daily challenges, and the strategies they've adopted to survive in an increasingly adverse environment. Join us for a closer look at the reality of those who work the land in difficult times.

In this section you will see a series of videos presenting information about the page and giving brief summaries about it.