REQUIREMENTS FOR INCORPORATION WELLS
Characteristics of Infiltration Wells
The increasing population growth and monetary development in Indonesia have pushed up the demand for housing. This has an impact on changes in land capacity and use. The shift to land use in open spaces makes residential land a trigger for the lack of rainwater absorption areas. Changes in the function of the land area will affect the condition of the water flow as a result of flood events peaking during the rainy season and becoming dry during the dry season.
Residential areas are very dependent on good water resources and are needed for the continuation of the life of many people, even all life around the area. Residential areas are in dire need of water and will continue to increase along with the increasing number of residents. However, measurably if the accessibility of surface water flow is minimal and subjectively the longer the water will decrease. One of the frameworks for environmentally sound water management that is not harmful to the ecosystem, both for handling floods and during droughts, is infiltration wells. Water absorption excavation is a way to strengthen the absorption of water that enters the soil cavity and reduce the upward flow of water that triggers inundation. The existence of a large and controlled drainage system and the increasing amount of overflowing water that can overcrowd the soil, the condition of the water in the soil will be good with the condition of the water in the soil and will benefit the community around residential areas. (Siswanto, 2001).
It is necessary to design infiltration wells according to standards when they are made because infiltration wells have the main function of protecting the direction of surface water flow and preventing catastrophic events from overflowing water and strengthening and raising the ground water level and more importantly it is hoped that the excavation of infiltration wells will be able to reduce the occurrence of erosion and preventing the entry of sea water for areas or areas whose land use is directly adjacent to the coastal area. Technically, infiltration excavation is a water conservation engineering science in the form of a facility similar to an infiltration well with a certain hole size and is useful for raising groundwater to the surface. Infiltration wells are holes to enter water into the ground which serves to accommodate rainwater that falls or water-saturated areas then enter the soil to seep into the pores of the soil and in the process of making these infiltration wells, efforts are made to increase the ability of the soil to infiltrate rainwater.
Infiltration Well Requirements
Based on Indonesian National Standard (SNI) No. 03-2453-2002, it can be seen that the general requirements that must be met for an infiltration well for the yard of the house are as follows:
- Rainwater infiltration wells are located on fairly flat land.
- When determining the position of a rainwater dug well, the condition of the safety level of adjacent buildings must be evaluated.
- Water that infiltrates into infiltration wells is in the form of spilled water that has not been contaminated with dirt.
- Local regulations must be taken into consideration.
- If there is an inaccuracy in the fulfillment of this provision, the approval of the competent office or agency in the area must be obtained.
This rule also stipulates the shape and size of infiltration wells including:
- This rainwater infiltration well model must have a rectangular or circular mold model.
- The pipe that goes into the ground is 110 mm
- The minimum side diameter of the well is 0.8 meters.
- The size of the well overflow pipe is 110 mm in diameter.
- The maximum side cross-section is 1.4 meters.
Infiltration Well Illustration
Syarat Umum Sumur Resapan
The water infiltration well to be built has the following general requirements:
- Digging wells must be avoided from landfills, septic tanks with the closest distance of 5 meters measured from the edge with a minimum distance of 1 meter from the foundation of a building.
- Water face (water table) the soil is at least 3.0 meters deep during the rainy season.
- Water absorption wells must be in a flat area or plane, not in an area that is hilly, steep or unstable.
- Digging of water absorption wells can be carried out up to sandy land or a maximum of 2 meters below the ground water level.
- Soil permeability (water absorption) soil structure must be more than or equal to 2.0 cm per hour (meaning that if the water is flooded as high as 2 cm it will easily seep into the soil and disappear within 1 hour), with three classifications, namely:
a. If the soil capability is moderate, that is, the absorption capacity is 2.0 – 3.6 cm per hour.
b. Absorption capacity for soil permeability is rather fast (fine sand), which is 3.6 – 36 cm per hour.
c. If the situation is fast soil conditions with coarse sand characteristics, which are greater than 36 cm/hour.
In general, the procedure for making water absorption wells is as follows:
- Field cleaning
The first step is to clear the area between the SRA development areas of plants, grass, shrubs, and shrubs that can hinder the work process. - Re-measure and peg the area of the dug well
Areas that have been designated with benchmarks must be re-estimated even as markers and are intended to determine the position and specific area of the structure and spillway and sedative tank areas. - Making Infiltration Wells
The technique of digging a well includes the following working steps:
a. Installation of profiles serves as a layout pattern/dredging barrier (wells and tubs). Depending on the design, the profile can be formed from woven bamboo or other materials.
b. Carry out digging of wells and control tanks.
c. After the excavation is complete, the well wall is then built. By mixing cement and sand and applied to the installation of brick/concrete as a reinforcing coating.
d. The control tub is built at a distance of approximately 50 cm from the SRA and is useful as part of a water hardness filter.
e. Drains are designed to collect rainwater that seeps from gutters and above ground water ditches to infiltrate the dug wells for a certain flow volume and quantity.
f. Materials used to fill the layers include crushed stone, heaps of palm fiber, and gravel, with the aim of filtering water that seeps into the soil cavity.
g. The runoff channel is made to make it easier to drain or dispose of water at the age of the infiltration that has been filled with water.
h. Cover plates for water absorption wells (SRA) can be made of reinforced concrete or iron metal plates, according to the conditions of need and availability in the vicinity.
i. Gutters must be installed according to the needs and available budget.
Infiltration Well Technical Requirements
Excessive subsidence of the ground water level can be overcome by increasing the position of infiltration wells. The indication of groundwater level reduction is when the well dries up or during the dry season and the water overflows during the rainy season. Improvements in the surrounding environment are the impact of increased development, in the form of opening new areas, indiscriminate logging, provision of community settlement infrastructure, construction of factories and manufacturing industries to trigger the incident.
One of the concepts or solutions for how to control water, whether it is facing a flood or a dry one, is through infiltration excavations. This seepage well is a manifestation of an effort to increase the entry of rainwater into the ground and reduce the direction of surface current flow and cause flooding. Some of the uses of infiltration wells are as follows:
- As Flood Control
- Groundwater protection
- Resist the rapid erosion at high speed.
- Located in a densely populated residential area;
- For ground cover vegetation <30% and located at a fairly high run-off;
- The structure of the soil layer that can be used must have a soil permeability value of 2.0 cm/hour.
- Preferably located in the upper and middle morphology of the watershed;
- For technical requirements the depth of groundwater in the rainy season is a minimum of 3.0 m;
- Placement of the position of the water absorption well to the location of the surrounding buildings by:
a. Placement of clean water wells as far as 3 m.
b. For the position of the RSP to the building foundation as far as 1 m.
c. Infiltration area for septic tanks, cubluks, sewers for dirty water, garbage disposal as far as 5 meters.
Concrete Buis Type Water Infiltration Well Design
(Source: Juknis RSP-DRH, 2021)
Specifically for the manufacture of water absorption wells, there are several SRA technical specifications that must be complied with based on: Peraturan Menteri KLH Nomor. 28 Tahun 2020 that is:
- The inlet pipe measures 110 mm in diameter with a maximum length of 4 meters.
- SRA which has a cavity is then filled with crushed stone with a thickness of 40 cm.
- Spill pipe size 110 mm with a maximum length of 4 meters.
- The depth is 2.1 meters and the walls are made of concrete and crushed stone that is arranged in a hollow.
- The water infiltration well is then filled with 10-20 cm of crushed gravel, 5 to 10 cm of broken red brick, several pieces of fiber, and chunks of charcoal.
- To secure the excavation of the water infiltration well, a cover tool made of concrete with a thickness of 10 cm and a mixture of cement, sand, and crushed gravel is used with concrete iron reinforcement 8 mm with a distance of 10 cm between the iron.
Infiltration Well Work System
One of the impacts that occur due to reduced water catchment areas is frequent inundation and even flooding. Flood is a natural event that cannot be ascertained and controlled. Various ways have been tried but still leaves problems. Floods that occur have a negative impact on public health. Diseases that many suffer from include diarrhea, digestive infections to dengue fever and various other diseases.
In addition to the negative impact on public health, it also has an impact on material and immaterial losses so that efforts need to be made to handle it. One of the efforts in dealing with flooding and inundation is to make infiltration wells that function to drain water into the ground. This infiltration well is one of the flood control efforts that can be done by collecting rainwater in a hole or well and soaking it into the ground. (Kusnaedi, 2011). The existence of infiltration wells can expand the water absorption area, be it wastewater from household waste or rainwater.
Infiltration wells also function as an effort to conserve soil and water in the soil. With these infiltration wells, it is hoped that puddle water caused by rain can be accommodated in the infiltration wells. Thus the chance of flooding and inundation can be minimized. In this chapter, we will discuss the working principle of infiltration wells, both simple infiltration wells and modern infiltration wells.
Infiltration Well Working Principle
In principle, the way infiltration wells work is to channel or drain rainwater that is on the surface and is accommodated into holes or wells that have been made. More and more water can be stored as groundwater below the earth's surface and can be utilized. Thus, it is hoped that excessive surface water and the cause of flooding can be minimized.
Before making infiltration wells, there are several things that need to be considered, including climate factors, this is related to the intensity of rainfall, the greater the rainfall in an area, the more infiltration wells are needed. In addition to climatic factors, it is also necessary to pay attention to the condition of ground water. In soils that have shallow water levels, the wells cannot function properly so this is less effective. Next is the condition of the soil that has an infiltration capacity that affects the size of the soil's absorption capacity of rainwater. This is related to land use or land use.
In addition to the things above, the socio-economic conditions of the community and the availability of materials also need to be considered in the manufacture of infiltration wells. Utilization of available materials in the vicinity can be conditioned with the environment and the availability of existing raw materials. The main materials that can be used in the manufacture of simple infiltration wells are:
- Pipes can be made of iron or paralon (PVC), bamboo, hongs of earth or concrete, and earthen trenches with stone. These materials are used to channel water.
- Well wall construction can be in the form of walls, used drums, concrete hongs, woven bamboo or fiberglass tanks.
- Gravel or palm fiber can be used as the bottom of the well and between the walls where water seeps.
Simple Infiltration Well
Simple infiltration wells can be made by all groups, both people in rural and urban areas. The designs and materials used are easy to obtain and simpler than modern infiltration wells. The stages of making this infiltration well are as follows:
- Make a cylindrical hole in the ground with a diameter of 10 cm to 15 cm and a depth of 100 to 120 cm. The thing to note is that at the time of making the hole it does not exceed the ground water level. Making these infiltration holes can be used iron pipes or earth drills and even bamboo with a distance between holes of 50-100 cm.
- After the cylinder bore is completed, the hole can be filled with organic waste. Organic waste in the form of compost can be used as plant fertilizer.
- At the end of the cylindrical hole can be surrounded by cement mortar as wide as 2 to 3 cm which aims to hold the surrounding soil from entering the hole.
Simple Infiltration Well Sketch
The way infiltration wells work is that the rainwater that falls will go through gutters and flow through pipes that enter the wells that have been made. The water will have a longer stay at the ground surface. This is because water is accommodated in infiltration wells.
Periodically the water will seep little by little penetrate into the soil surface and make groundwater recharge so that the water discharge will increase. This will increase the amount of groundwater in the aquifer layer. An aquifer is a layer in the soil that has rock formations that are able to accommodate, release and pass water even in large quantities.
Infiltration wells made in the conventional way have a limited capacity. If the amount of water in the infiltration well has crossed the surface of the infiltration well, the water will flow through the available pipes to the sewer or drainage. With infiltration wells made, there will be more groundwater than if the water only flows on the ground surface, this is known as water conservation.
Through this groundwater conservation, it is hoped that there will be an increase in the amount of groundwater discharge so that the need for clean water and water below the surface can be met even during the dry season.
Modern Infiltration Well
The working principle of modern infiltration wells is basically the same as conventional infiltration wells. But the difference lies in the size and materials used. This modern infiltration well is in the form of a practical modular tank made of polypropylene. The modular tank can absorb water and be accommodated which can then be reused at some point in time. The use of modern infiltration wells in the form of modular tanks is worth considering.
Currently, water storage by saving rainwater in infiltration wells with modular tanks has become popular. The water contained in this modular tank can also be used for watering the garden, washing the car or flushing the toilet.
Most people in Indonesia have not used rainwater. Only a small part of the community has made use of rainwater. So far, rainwater is only thrown away and flows away without being reused. The advantage of collecting and collecting rainwater, among others, is to protect the availability of ground water which is felt to be increasingly scarce, especially during the dry season. In addition, as an effort to minimize the difficulty of obtaining clean water, especially in areas with minimal rainfall. The following are pictures and explanations of modern infiltration wells.
Illustration of Modern Infiltration Well Installation
Modern infiltration wells use modular tanks which have a more practical way of working. Water entering the infiltration tank is accommodated in a tank that has been lined with a non-woven geotextile sheet. Slowly the water will pass through the non-woven geotextile by seeping. The condition and level of soil permeability greatly affect the rate at which water is absorbed. The excess water that enters will be channeled through the over flow pipe that has been prepared. The water is channeled into the local environmental canal. This condition can occur if the amount of water absorbed by the soil is smaller than the amount of water that enters.
If this modular tank is used as a water reservoir, the module is closed using a geomembrane on all sides so that water can enter and be retained in the tank. If the amount of water entering exceeds the capacity of the tank, the water will spill out through the overflow pipe that has been prepared. The position of the modular tank can be arranged vertically or horizontally using an interlocking system that is placed under. The land above the modular tank can be used as a carport, garden or other use. Modular tanks are generally used as a storage and collection of rainwater (rain water harvesting) with the aim that rainwater is not wasted. The water in this modular tank can still be used for daily needs.
