How to dig a pit under a pond, lake, pool or well properly?

Making a water feature on your property, such as a well, lake, pool, or pond, can make it feel like a tranquil haven. But before you can take pleasure in your new water feature’s beauty and tranquility, you must first complete the necessary preliminary work: excavating the pit. The stability and durability of your project are guaranteed when a pit is dug correctly.

The process needs to be carefully planned and carried out, regardless of whether your goal is a small garden pond or a larger lake. Before you start digging, make sure you understand the water table, type of soil, and required permits. You can steer clear of typical pitfalls and lay a strong foundation for your water feature with the correct planning.

We’ll walk you through the process of properly excavating a pit in this guide. Everything will be covered, including selecting the ideal site, estimating the size, operating the excavation equipment, and making sure the drainage is adequate. You’ll be well on your way to building a stunning and useful water feature on your property if you follow these instructions.

Features of digging

A pit beneath a pond is a man-made indentation in the earth intended to be filled with water later on and utilized for specific purposes.

One characteristic of reservoir pits is that their borders need to be stable in relation to the amount of water that will be placed within them. The intended use of the future reservoir will dictate the pit’s profile, shape, size, and depth.

Three primary categories can be used to categorize reservoir pits:

• under the lakes and ponds;
• under the pools;
• Under the wells.

We’ll examine each one in greater detail.

Under an artificial pond

Pits used primarily for artificial reservoirs fall into one of two categories:

• Decorative. As a rule, small pits located in a semi-shaded place where the sun hits in the morning and evening. This is important for maintaining the vital activity of all microorganisms in the reservoir. It is more appropriate to make the profile stepped.
• For fish farming. Usually a large pit with a depth of at least 1.5 meters. The relief should be divided into zones of different depths, including a wintering pit, the bottom of which will be 150 cm below the soil freezing level.
• For swimming. The most common option is a smooth descent to a depth of up to 3 meters. If the pond is shallow, it may begin to bloom. The deeper, the colder the water below, and therefore no flowering occurs. You can make a sandbank for easy entry, where the water will warm up.
• For recreational use. Such reservoirs must be large enough, with a high water exchange coefficient.

The size, depth, and bottom topography of each type of lake reservoir are the primary distinctions between them.

Under the well

Digging pits for mine wells necessitates three different kinds of pits:

• Imperfect.
• Perfect.
• Perfect with a sump.

Their designs and pit depths are strikingly similar to one another. There are differences between these wells in terms of construction nuances and water supply techniques.

Under the pool

Pool shapes include:

• square,
• rectangular,
• trapezoidal,
• round,
• oval,
• decorated to look like natural bodies of water,
• with straight walls,
• with inclined walls.

Furthermore Bowls of various compositions are used to install them:

• concrete,
• plastic,
• polypropylene,
• composite compositions.

The strongest and most resilient bowls are made of concrete, but installing them is costly and takes a lot of time.

Size calculation

The amount of work that will actually need to be done for soil removal and excavation depends on how big the future depression in the ground will be. This must be determined beforehand. Several techniques and formulas for calculations are chosen based on the characteristics of the terrain and the ways in which work is done.

To determine the pit’s size, the following information is required:

1. Depth.
2. Length and width along the bottom.
3. Length and width at top.

Complex shape recesses must be calculated by dissecting them into simple geometric bodies, counting each one separately, and adding them all up.

Here’s an illustration of how to compute a rectangular pit:

• H – depth;
• a and b – width and length along the bottom;
• c and d – width and length at the top.

Using specialized calculators for calculating earthworks makes the process of calculating dimensions simpler and faster. It is necessary to specify all parameters in meters in order to prevent potential errors during automatic calculation.

The calculator can be used not only when organizing the work but also when modifying object parameters while excavating.

You can use the following extra tools to make sure soil volume calculations are as accurate as possible:

1. Topographic survey.
2. Office processing to establish additional points and correct calculations.
3. Assessing the geological parameters of the site.

After that, a technical report is created that includes all of the errors and computation outcomes.

For artificial lake

The area on which a pond or lake will be located must be taken into consideration when choosing the pit’s size.

A lake or pond can be more expansive the larger the territory.

A water body’s size should be determined in a ratio of 1:30 to the territory’s area. Such a pond won’t need needless labor and will have a harmonious appearance.

A pond’s minimum depth should be 0.5 meters; for ornamental ponds, 0.8–1 meters is ideal; and for fish farming, at least 2 meters. Strict straight lines should be avoided if you want the pond to have a natural appearance.

For a well

The well is a long, reinforced pit that is 5 to 15 meters deep. You can pre-drill a well or compare the dimensions of nearby structures to determine the minimum depth required in a given area.

For the pool

Beyond the bowl itself, the pool pit needs to have the following:

• sand cushion,
• formwork,
• pipes,
• embedded elements.

As a result, the entire perimeter of the pit is made about 0.5–1 m wider than the bowl’s size.

The material of the bowl also affects this size. Concrete walls, for instance, are wider than composite ones.

For a pond, lake, pool, or well, a well-excavated pit is necessary to guarantee stability and functionality. It’s important to carefully plan the size and shape, select the ideal location, and use the right tools when digging. Mark the area first, taking drainage and soil type into account. Dig gently, keeping the depth and slope constant, and be sure to get rid of any big rocks or roots. Excavation done correctly provides a stable base, less maintenance down the road, and a long-lasting, safe water feature.

Creation technology

It is vital to research the future location of a reservoir and determine the following before beginning to design one:

• type and geophysical condition of the soil;
• resistance to subsidence and shedding;
• groundwater level;
• presence of hard calcareous rocks;
• presence of underground gases.

When organizing and completing tasks, this information will help to prevent numerous errors.

Requirements for slopes

Pit slopes must meet specific criteria. A departure from the norm could cause the recess’s walls to collapse.

The earth’s density and the hole’s depth are the decisive factors:

One small factor is the duration of the recess. It is uncommon for large straight sections to collapse over short distances.

Work on creating a hole for a lake or pond

When building an artificial reservoir, planning is the first step you take. Drawing a sketch on graph paper is preferable.

Planning

The following is how the planning process works:

1. Using a compass, the south and north sides are determined and markings are made on the plan.
2. Objects that cast shadows are marked (buildings, large trees, fences). This should be done in sunny weather during the day every 2 hours, reflecting on paper places of partial (blessed for 4-6 hours) and full shade. Partially sunny locations are ideal for placing ponds. Under such conditions, flowering can be avoided without harming the vegetation and inhabitants of the reservoir.
3. Selecting the optimal location on the site for a pit for a pond. There should be no underground utilities or large objects laid nearby.
4. The type of pond is determined by its purpose.
5. The dimensions of the pit, its depth, shape and profile are being worked out. Data to scale is plotted on the plan.
6. The pit zones are being worked out, taking into account their purposes and design.

Land works

Once the plan is developed, you can start clearing the space and digging the soil. These tasks are completed step-by-step over a number of stages:

1. Preparing the site for a pond.
2. The area is marked according to the sketch. You can use twine and pegs for this.
3. Excavation of soil with an excavator or shovel. If work is carried out using an excavator, then it must be tracked with a rotating tower and a 1-2 cubic meter bucket. It is better to start digging from the edge, gradually moving towards the center, going deeper in the right places. During work, you need to check the uniformity of heights using a level. The banks must be at the same height relative to each other. You can adjust the height using the soil left over from digging a pit.

The proper completion of each step determines the final outcome and reservoir quality.

Under the well

Digging a well is not a job best done at any time of year. When the aquifer is at its lowest point in the summer, it is preferable to do this. This will lessen the possibility of inaccurate groundwater level determination.

Planning

The same as when excavating a lake or pond, you must first create a sketch that accounts for the following details:

1. Selecting a location. The pit for the well must be located at least 5 m from large buildings, otherwise there is a risk of soil being washed out from under the foundation. Also, at a distance of 50 meters from the well there should be no places where manure and other impurities are located. This may affect water quality.
2. Planning a method for strengthening the walls of the well. The walls can be strengthened using materials such as:
3. Wooden frame – budget, but short-lived.
4. Monolithic concrete – expensive but reliable.
5. Brick takes a long time to install, but, like concrete, it is reliable.

Following the plan’s creation, the chosen area is cleared, and ground markings are made. You can then start working on land.

Land works

An excavator can be used to dig the well pit mechanically or by hand. Let’s examine each of these approaches’ characteristics in turn:

• When digging with an excavator:
• Temporary placement of the excavated earth should not be close to the pit, so as not to collapse its walls.
• It is necessary to monitor the depth of the pit and the condition of the walls, pay attention to any delaminations. If the delamination turns into a series of collapses, stop work, fill up above the collapse level and contact professionals.
• If the influx of groundwater is insignificant, the walls must be strengthened and work continued manually.
• When digging manually:
• Ideally, the work is carried out by three people: the first is in the pit and removes soil, the second is at the top scraping soil from the edge of the pit, and the third monitors the condition of the pit system and the worker inside. If they change roles every half hour, work will go quickly and without stopping.
• The pit should be round, with a diameter 20-30 cm larger than the outer diameter of the rings. Round walls are more stable.
• If the pit is deeper than 2.5 meters, then its walls need to be strengthened: when this depth is reached, 2 rings are lowered into the pit – they become natural protection for the person working in the pit. Then the soil under the lower ring is gradually dug in a circle, and it lowers under its own weight. If the expected depth to be dug is greater than the height of one ring, then you need to fasten the rings together with plates using anchor bolts. Otherwise, the upper ring may be pinched by the ground and will stop settling along with the lower one.

Whether excavated manually or by machinery, the bottom needs to be cleaned and leveled. Next, the pit is inspected and the walls’ depth and slope angles are adjusted if needed.

Under the pool

A schedule of earthworks must be created, accounting for seasonal variations in groundwater levels. Since groundwater is at its deepest in the summer, it is advised to begin work then.

Planning

Engineering studies are required to gather data regarding the characteristics of the soil before planning can start.

After that, a sketch is created using the advice that follows.:

• Place for the pit you need to choose outside the area where utility networks are located. It is worth considering the location of the place relative to the buildings. If proximity to them cannot be avoided, then the soils of existing structures must be strengthened.
• At high groundwater levels you need to think about ways to reduce water on a temporary or permanent basis. For temporary water reduction, a depression is made with a slope below the bottom of the pit. For permanent – ​​drainage.
• When choosing a pool profile shape, you need to consider the following nuances:

• It should ensure the stability of the bowl and prevent its erosion.
• The optimal slope configuration is stepped. The height of the ledges is about 30-40 cm. This ensures maximum operational safety and increases the service life of the pool.

Butyl rubber, reinforced concrete, or prefabricated polypropylene bowls in different sizes and shapes can be utilized as the pool’s foundation.

Land works

Because excavation work requires a lot of labor, using an excavator makes the task easier. It is advised to choose a soil volume that is roughly equivalent to the pool’s volume with a small margin when utilizing mechanized excavation, and to finish the excavation by hand.

Primary Earthwork Stages:

1. Marking the shape and dimensions of the pit.
2. Removing the top soil and plant layer to a depth of 20-30 cm.
3. Removing the second layer with an indentation of 30-40 cm from the edge. This is done to create an indentation that will serve as the edge of the pool, preventing erosion of the coastline. In the future it can be decorated.
4. Deepening the pit to the design level. The bottom and slopes are leveled, compacted and protected from erosion with a layer of sand 5-10 cm thick and waterproofing material.

To safeguard future waterproofing, any stones or thick roots discovered during the excavation process must be removed.

Possible mistakes

Errors and defects in pit excavation and design can cause the reservoir’s functional properties to deteriorate and deform.

The most typical errors consist of:

• Right angle of slope of the pit walls for a pond. In winter, with such a steep slope, the freezing soil will put pressure on the walls of the bowl, deforming them. The slope should be 45°, then optimally distributed pressure prevents landslides. Also, with such a slope, the decorative elements of the inside of the bowl do not slide anywhere.
• Lack of gas drainage in pits for decorative ponds. Leads to pressure of subsoil gases on the membrane and raising of the film. It is necessary to remove subsoil gases.
• Subsidence of the pool bowl after filling with water. Occurs due to insufficient soil density. It is necessary to remove all loose soil from the bottom of the pit.
• Lack of water flow in low-lying bodies of water. Low-lying reservoirs can overflow with melt and rainwater. If there is a lower place on the site, then you can dig a trench under the drainage pipe and release excess water through it.

Step	Description
1. Plan the Location	Choose a suitable spot for your pond, lake, pool, or well, considering factors like sunlight, drainage, and accessibility.
2. Mark the Area	Use stakes and string to outline the shape and size of the pit. This helps you visualize and stay within boundaries while digging.
3. Start Digging	Begin digging from the center, working your way outwards. Ensure you dig evenly and gradually, maintaining the shape you marked.
4. Check the Depth	Periodically measure the depth to ensure you reach the desired level. Adjust your digging as necessary to maintain uniform depth.
5. Smooth the Sides	Once the desired depth is reached, smooth the sides and bottom of the pit. Remove any large rocks or roots to create a clean, even surface.
6. Install Liners (if needed)	For ponds, pools, or wells, you may need to install a liner to prevent water from seeping into the ground. Lay it carefully to avoid tears.
7. Add Finishing Touches	Complete the pit by adding any necessary plumbing, pumps, or other equipment. Finally, fill the pit with water and make any final adjustments.

Careful planning and execution are necessary when creating a pit for a lake, pond, pool, or well. Comprehending the distinct prerequisites for every category of water feature guarantees the triumph and durability of the undertaking. Start by selecting a good spot, keeping in mind elements like soil type, sunlight, and distance from other structures.

Once the location has been chosen, precisely mark the dimensions to direct the excavation process. Whether you’re doing the digging by hand or with machinery, make sure you have the appropriate tools and equipment. Safety should always come first, so to avoid mishaps, wear the proper clothing and adhere to safety regulations.

In order to prevent collapses, reinforce the sides of the pit if needed after it has been dug to the appropriate depth and shape. Installing a liner in lakes and ponds helps keep water levels stable and stops leaks. Additional procedures, like installing a base layer or casing, might be required for pools and wells.

It is also essential to manage the excavated soil properly. Use it as landscape material or dispose of it in accordance with local laws. Lastly, before adding water or carrying out further construction, make sure the pit is stable and make any required corrections. This meticulous attention to detail guarantees that your water feature will be a stunning and useful addition to your home.

Video on the topic

Don"t repeat these mistakes! DIY pond.Pond at the dacha. Pond on the site.

How to dig a pond with an excavator, detailed instructions! youtube 2025

How to dig a pond all stages in one video

How to dig a pit for a reservoir or pond (part1)