Implementing an earthwork in a landscape becomes a straightforward decision when following the appropriate protocols. This article explores the relevant factors and design principles that aid in the selection of suitable earthworks within a well-defined context. Despite its simplicity, this regenerative technique demands careful consideration, particularly when employing fossil fuel-powered machines.
#1 Start with a design strategy
The earthworks team should strive to deliver a feasible, functional, and constructible earthworks design that suits the intended end use. They should consider all temporary works and land requirements. It is crucial to develop a design that minimizes environmental impact throughout construction, usage, and future maintenance operations.
#2 Don’t interfere unnecessarily
Disturbances caused by earthworks should only be undertaken when absolutely necessary, not simply because an appealing video sparked an interest. If there is no apparent flow into the area due to various reasons, it is advisable to refrain from carrying out earthworks. It is crucial to consider factors such as water flow, soil types, slope percentages, and other relevant factors before attempting any earthwork.
#3 Transition to the digital world
Earthworks design and planning are now carried out using digital documents and mobile technologies. You don’t even need professional surveying equipment to do most types of construction. For example, you can run GPS and get relatively accurate data. If necessary, you can Android geo-location update or fake it. This approach can be used if you need to unblock some website, or software, or hide your actual location. In this way, the smartphone can serve as both a tool for determining location and circumventing geolocation-based restrictions.
#4 Call before you dig
This phrase is popular in the United States because it’s crucial to avoid damaging utility lines. Therefore, utility crews precisely determine the location of all lines to facilitate design planning. In rural projects where wiring or piping may not have been professionally installed, it’s advisable to seek multiple opinions on the whereabouts of each line from project participants.
#5 Soil research
People often express their desire to create water-retention landscapes or swales without considering the soil conditions. It is crucial to assess the soil before embarking on such projects, especially if you intend to construct water retention dams or ponds. Even in clay soils, like those found at Suryalila Retreat Center in Southern Spain (2017), building dams may not be feasible.
Despite being informed of this, the owners of the retreat center decided to proceed with a test dig, which cost only 50 Euros. As predicted by the driver, we encountered a layer of broken junk base rock about 1.5 meters below the surface, rendering any dam excavation futile. Similarly, in areas with sandy soil, such as my family’s land at Treasure Lake in Kentucky, USA, where there isn’t significant runoff, constructing swales is unnecessary since the water naturally sees into the ground. Therefore, in that specific part of Treasure Lake, there is no need for intervention. However, for the heavy clay soils on the other side of the valley, intervention is necessary due to the higher risk of landslides, often requiring professional advice.
#6 Perform a soil compaction test
For most types of soil, you should choose the upper and lower acceptability limits based on a specific ratio of dry density to the maximum dry density. The commonly used criteria are 95% of the maximum dry density determined through the 2.5 kg light dynamic compaction test or 90% of the maximum dry density determined through the vibrating hammer test for bulk earthwork fill. Fill that will support structures and where settlement is more critical will require a higher value, up to 100% of the maximum dry density.
#7 Conduct an environmental impact assessment
Not all structures can be built at the request of the developer, as they may have a more global impact on the economy and the environment. For many types of buildings, it is mandatory to conduct an environmental impact assessment. This document is often necessary for issuing a permit and can adjust the developer’s plans for construction.
#8 Layout contour lines in the field
Measure the contour lines in the field using the available surveying equipment such as A-frame, bunny, transit or dumpy level, or laser level to obtain an accurate depiction of the land’s layout. While contour maps are helpful, the field’s details often differ slightly from the topographic map. Mark these contour lines with flags to enhance the accuracy of landscape interpretation.
#9 Project management
Before you begin any earthworks, ensure that you have all the required resources for land restoration. While complete organization may not always be possible, certain aspects must be prepared in advance. These include soil covering techniques like cover crop seeds or mulch, methods to restore soil biology such as compost extract or compost itself, adequate water supply, and means to stabilize the earthwork, such as trees and their associated guilds.
It is crucial to perform the excavation or land alteration when soil moisture levels are optimal, considering the timing aspect of project management. Clearly communicate the budget to the client, as earthworks are just one part of it, and allocate sufficient funds for the other necessary items. Once all resources are accumulated, initiate the implementation, including skilful orchestration and diligent physical labor for tasks like earth sculpting, tree planting, cover cropping, watering, mulching, and more.
#10 Ask for advice from professionals
Consult engineers, machine drivers, and permaculture consultants if you have any doubts about your actions. You need specialists who perform geotechnical engineering for earthworks and are well-versed in the matter. In certain parts of the world, you may need government permission and engineer approval, so familiarize yourself with the local laws and don’t hesitate to seek an engineer’s advice.
Be aware that building a dam can be a bureaucratic process, and there have been reports of landslides caused by overly audacious permaculture earthwork enthusiasts. I can confirm that one such fanatic charged a hefty fee for a design in Southern Spain that included dams, even though building one would be practically impossible due to water regulations.
#11 Observation and execution
Always maintain a vigilant watch over machine operators and working crews. Fatigue can lead to shortcuts and decreased precision. It is crucial to stay alert and motivated. Communication with machine operators largely relies on hand signals and eye contact after explaining the initial design. Do not hesitate to slow down machine drivers and implementation crews to ensure adherence to design specifications. Be prepared for on-site modifications as moving the earth often necessitates minor adjustments.
It is impossible to cover such a large niche within a small material. However, some advice on cost-effective earthworks construction was still included. You can actually save money on some jobs, but tasks such as compaction testing and quality control are an investment in the future. Saving on this issue can lead to incorrect calculations of load-bearing structures, cracks in the building, and even violations of the law. Savings must be reasonable and justified.