Nimrod Environmental limited

Q. I've got a Japanese Knotweed infestation, what do I do?

A. Firstly, don't panic. Are you sure that it is Japanese Knotweed? Email photographs to us and allow one of our surveyors to take a look.

Email your photographs to enquiries@nimrodenvironmental.co.uk

Q. Do I need to take action if I have Japanese Knotweed on my land?

A. There are no statutory requirements to eradicate Japanese Knotweed if it is on your land, however you have a legal requirement to stop it spreading from yours onto adjacent land. Remember that early treatment of an infestation is vital as it will rapidly spread, the longer you leave it the more expensive treatment will be.

Q. When should the problem of Japanese Knotweed be tackled on a development site?

A. Japanese Knotweed should be addressed during the early stages. It will often be picked up during ecological surveys on large sites, however, it is very important not to allow demolition contractors or groundworks to begin before the the site has been properly inspected.

Q. What are the different options that can be used for eradicating Japanese Knotweed?

A. Chemical treatment is by far the cheapest option for eradication of Japanese Knotweed. Chemicals can be applied by both spraying and direct chemical injection into the plants. There are a number of chemicals on the market which can be used for eradication of Japanese Knotweed and other invasive weeds which fall into two distinct categories.

Non-Residual herbicides

These herbicides are translocational which means that when applied directly onto live plant tissue they pass through the system into the roots and kill the plant from within. They are the only chemicals which can be used within 5 metres of a watercourse provided that Environment Agency approval is granted through a WQM1 notification form. Complete eradication of Japanese Knotweed using these methods can take between 3 and 5 years of repeated treatment.

Residual Herbicides

These herbicides bind to soil particles and from a barrier within the ground which can persist for up to 2 years. Surface growth of Japanese Knotweed can be eradicated within 12 months of the growing season however underground rhizomes can still be viable for a number of years, therefore if this barrier is compromised through excavation or other disturbances then re-growth can still occur.

Excavation

On development sites there are often time constraints for treatment of Japanese knotweed, excavation and relocation of the contaminated material on or off-site can often provide the solution. Due to Environment Agency guidelines of root growth which is 7 metres either side of visible stands and 3 metres down the volume of potentially contaminated material which needs to be treated can be very large. Nimrod Environmental have experienced staff who can follow the root structure ensuring that it is all removed without excavating unnecessary material. There are a number of methods which can be employed depending on your site requirements.

Excavation and Relocation to Waste Management Area

If the Japanese Knotweed contaminated material is within the build zone of proposed buildings it can be relocated to an area of the site which is not going to be developed in the near future or an area of POS. Here chemical treatment can be carried out and in many cases after treatment is complete the material can be incorporated into soft landscaping.

Excavation and Burial on-site

If space is more limited a borrow-pit can often be the best solution. The contaminated material is buried under a minimum 2 metres of clean fill encapsulated within a sealed geo-textile membrane.

Excavation and Removal to Licensed Landfill

If there is very little space for on-site treatment then the only remaining option may be to take the material off-site to a Licensed Landfill. This option is the most expensive however is a very fast solution to the problem.

Root Barrier Systems

Our root barrier systems use the latest technology in geo-textile membranes, welders and adhesives to provide effective protection to your site. We utilise our root barrier systems in a number of situations such as encapsulation in on-site borrow pits, boundary root barriers and they are also successful in the footprints of buildings which have already been built on Japanese Knotweed contaminated land.

Q. What is a Green roof?

A. A Green roof is a roof covered in vegetation and a growing medium. Nimrod encourages clients to consider the installation of a green roof on any flat roof space on their buildings; home or office as they have many environmental benefits. Some green roofs use a waterproofing membrane (sometimes a root barrier and drainage and irrigation systems too) and then the space is covered with vegetation; this can range from grasses to fully grown trees. There are two main types of green roofs – extensive or intensive, the difference explained below.

Q. What is the difference between extensive and intensive Green roofs?

A. Extensive Green roofs are thinner in depth and have less numbers of layers, they are lighter, less expensive and need low maintenance. Extensive Green roofs are chosen when the need is for an ecological roof cover with limited human access. Extensive Green roofs can be constructed on slopes up to 30°, and steeper ones can be installed with raised grids or laths to hold plants and soil media in place.

Intensive Green roofs tend to be relatively flat and look like traditional roof gardens because a much wider variety of plant material can be used as growing media depths are increased. Intensive Green roofs need a higher level of maintenance but features such as waterfalls, ponds and gazebos are possible which enables the roofs to act as recreational spaces encouraging interaction between people and nature.

The roof function or objective of the roof space determines the design – is it just an ecological cover or is it intended for human recreation, vegetable gardening, etc.? The limiting factors for Green roofs include:

• Roof loading capacity
• Maximum dead and live weight loads - determined by a structural engineer
• Slope of the roof
• Client budget

Q. What are the environmental benefits of Green roofs?

A. Green roofs serve several purposes and provide many ecological and aesthetic benefits, including:

• Controlling and absorbing rain water runoff
• Providing insulation
• Reducing the urban heat-island effects, cooling and cleaning the air
• More than doubling the service life of the roof by limiting damaging UV rays as well as daily temperature fluctuations, which causes repeated contraction and expansion.
• Conserving energy
• Reducing sound reflection
• Creating wildlife habitat, and
• Improving the aesthetic environment in both work and home settings.

Q. Why choose Nimrod to install your Green roof?

A. Nimrod will advise you on the best type of roof to choose and assess the loadings and waterproofing to ensure that you can enjoy all the benefits of your green roof. What a great way to lower your company’s carbon footprint!

Q. What are SUDS?

A. SUDS or sustainable urban drainage systems enable surface water to drain away through a collection of storage areas which steadily filter and clean the water so it can be released slowly back into the environment in appropriate places, such as natural rivers and streams.

SUDS reduce the impact of drainage discharges in urban areas where there is a higher proportion of less porous surfaces (tarmac and concrete) and fewer porous areas (grass land) where water naturally soaks away.

Q. How are SUDS constructed?

A. SUDS can be constructed in a number of ways, here are a few examples of techniques which effectively slow down and treat runoff water:

• Permeable surfaces – specially designed block work which allows passage of water through its surface to storage or soakaway.
• Filter strips – Strips of grass bordering which are designed to receive water from hard-standings. The strips remove sediment and pollution from runoff water.
• Swales – Shallow sided ditches which are planted with grass. Designed to slow the passage of water.
• Bioretention areas – short term water storage areas, often planted with shrubs and trees.
• Sedimentation ponds and basins – Longer term storage of runoff.

Q. What are the environmental benefits of SUDS?

A. SUDS replicate natural drainage systems (such as grass land and marshes) in areas where they are limited or there are no such thing (urban areas). SUDS reduce the effects that the surface water run off from one site has on other sites. Excess surface water run-off can lead to urban sewer flooding, however if all development sites installed SUDS then urban sewer flooding would be less of a problem.

Conventional drainage systems do not control water flow and this can lead to flooding and pollution of the environment in storm conditions. Knock-on effects include harm to wildlife and contamination of groundwater sources which are used to provide drinking water.

SUDS control storm water overflow, and therefore potentially improve water quality in watercourses. They also provide habitat for wildlife.

Q. Why choose Nimrod to install your SUDS?

A. Nimrod Environmental offers a complete SUDS design and installation service. We use cost effective materials which have low environmental impact so our SUDS replicate natural systems and reduce the effects that the surface water run off from one site has on other sites.

Nimrod installed SUDS are resilient, they require little or no maintenance and we ensure that they are environmentally friendly as well as aesthetically attractive. They can also provide a habitat for wildlife and protect and enhance ground water quality.