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our lawn is clay. we recently removed an old pool which left a layer of sand in the yard. i have researched enough to know that mixing sand with clay creates something less porous than clay. if i left the layer of sand without mixing it with clay, would the area drain. we are also going to build a berm at the back of our property to regulate water drainage from the property behind us. can we use sand, rocks, some fairly new pine chips, and clay. will the pine chips make the berm too porous as they decay thus defeating the purpose of the berm which is to hold back to redirect water.

Thank you

Answer
Hello,

Depending on how fine or coarse,sand has relatively good drainage properties. A good method to make clay more porous is to add organic matter. A small amount of coarse sand or gravel should not cause any problems and certain types of crushed rock may be helpful.

Do not use pine chips in the berm or any other organic material. Organic material will interfere with compaction and could create voids and contribute to seepage through the berm. You are correct,it will increase porosity. Also,do not use sand or rocks in the berm. Do not use cracking clay. This is a clay that has a high shrink/swell potential. In other words,it changes volume too much between being wet and drying. Do not use topsoil or sodic soil. Sodic soil contains high amounts of sodium chloride or sodium carbonate and is found in semi-arid or arid regions. The sodium carbonate type is alkaline. This type of soil is unstable. Calcitic clay is also unstable.
Rock and sand will also lead to instability of the berm.  So,basically, do not use the following for the berm:


organic material

topsoil

sand

rock

calcitic clay

cracking clay

sodic soil

fine silt

A good soil for the berm would be one with a relatively high and stable clay content. The clay will decrease the permeability of the soil. Some seepage may occur through the berm but depending on how long the water side of the berm is flooded,this may or may not be a problem. Riprap (stones placed on the water side of the berm) may be helpful in preventing erosion of the bank. A keyway at the base of the berm,consisting of impervious clay may be helpful in preventing seepage or a toe drain may be used. An alternative to a berm could be a concrete or masonry flood wall. An impermeable rubber lining may be helpful on the water side if suitable soil cannot be found to construct the berm. Other materials for the lining could include asphalt or concrete.

Plant a grass such as creeping bent or meadow grass on the berm to prevent erosion and to prevent deeper rooted weeds from moving in. These grasses are more suited to berms than ordinary lawn grass. Deep rooted plants such as shrubs are not desirable.

Before beginning work on this berm,be sure you can legally block water from your neighbors property. If this will cause flooding on your neighbors property or alter the natural drainage flow from your neighbors property,then you cannot legally alter the water flow. There are only limited circumstances where you can block water flow from a neighbors property,usually when the neighbor is causing water to be deposited on your property artificially,such as through a misplaced drain pipe. And sometimes even when the neighbor is in the wrong and is causing your property to be flooded,it is still not legal to block water flow,such as when a neighbor leaves a hill in an eroded condition causing excessive runoff onto your property. In this case,a court order must be obtained to have the neighbor correct the condition. Blocking water flow in such a case would cause flooding on the neighbors property by altering the natural flow of water. In general,always try to avoid flooding your neighbors property.  Good luck.

Mark Harshman


For more comprehensive help check out my website at:

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Design of landscape structures and design of planting arrangements in the landscape. I usually do not answer questions of a horticultural nature or about growing plants or gardening unless they are related to design. I will answer these questions at my discretion. I will answer maintenance questions at my discretion,usually when they are related to design. I am a landscape designer. I am not a contractor or a gardener. Although I will describe how something is built I do not provide detailed installation or construction instructions. Here are example categories of problems I can help you with: Design of residential walks,low walls,low retaining walls,fences,drainage systems,arbors,plant selection,xeriscapes (low water use landscapes),rain garden design,rain water harvesting,permeable paving,sustainable drainage. No advise on an architectural or engineering level. I DO NOT PERFORM ACTUAL DESIGN WORK THROUGH THIS SITE. I only provide suggestions and advice. For more comprehensive help check out my website at: http://www.prestoexperts.com/expert/markland

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Landscape concept plan for a 30,000 square feet housing site. Involved site recon by pace measurements and photographs and a site analysis and a site analysis report and recommendations and a preliminary cost estimate. Design elements included canopy trees,shrub cover,accent flowers,trash receptacles,benches and planters. Landscape concept plan for a 7,000 square feet site for a community center. Involved site recon by tape measurements and photographs,a site analysis and the creation of 3 conceptual designs for the site. Work was done through a local professional design center. Design elements included tree garden,playground,sitting area,lawn,cooking area,lighting and concrete and brick paving. Landscape concept plan for a 3,000 square feet housing site. Involved site recon by tape measurements and photographs and a site analysis. Concluded in 3 concept designs for the site,shown at a formal presentation,a site analysis and recommendations. Work was done through a community volunteer program. Design elements included decks,a playground and fencing. Briefly as draftsman for landscape designer/gardener. Conceptual landscape design for residence. Involved site recon by tape and pace measurements and site analysis. Design included covered patio area,ground cover and flower beds. Two years experience as draftsman for transportation department in engineering firm and for engineering consultants to phone company. Duties consisted of plotting topography. Survey crew member. General assistant to surveyor. Work was done for U.S. Army and County Highway Department. No instrument work. Duties included tape measurement,holding graduated survey rod and plumb bob for sighting and clearing brush. Marketed Landscape Design Services. Brochure writing,promotional material and marketing graphics.

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Course in Computer Aided Drafting. 700 hours in AutoCad 2000. 700 hours to date on AutoCad Light 2000. Certificate in Manual Drafting. 1200 hours drafting time. Course in Civil Engineering Technology. (One Semester)

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From Civil Engineer: I am very impressed with your work and with the obvious thought you have put into the marketing of your venture. It was especially good to see a print of that job we discussed on the phone. I wish you much luck with the venture as I do with your plans for school. Im darn proud of you buddy. And by the way,when I get my license,maybe you will consider me for a consulting job down the road. I hope to get together with Rick sometime soon and I would really like to show him your stuff if its ok with you. From all these questions you ask I get the feeling that you are genuinely interested and have put alot of thought into the idea and process of landscape architecture and if you could possibly afford the cost I would urge you to take some classes in the areas you are most interested in. The subject is not so simple as it appears,mixing science and engineering with art and a certain amount of religion to create a comfortable and pleasing balance between man and nature. A thoughtful soul like yours can do this but it can be a lifes work getting it right.

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