East Clayton Rain and Drainage Simulator

Transcription

1 East Clayton Rain and Drainage Simulator

2 Introduction This is a hard copy of the East Clayton Rain and Drainage Simulator. The simulator allows you to explore the impacts of the rain and associated runoff as it moves through the drainage system and eventually to North Creek. The images represent 3 modes of development that show the different methods of land use, and how the effects of rain are handled either by the area naturally, by typical development or improved with sustainable development methods. In each state, you will see how a light rain and heavy rain affects the runoff and drainage systems. With each scenario you will also find how a short or long rain duration can also affect the systems. A light rain we might consider as a shower, where a heavy rain may be a downpour. In the case of our scenarios, a short rain is roughly a 6 hour period of rain, while a long duration might be a 24 hour rain. For additional information on Rainwater Management check out the Water Bucket Website. It's goal is to inform British Columbia local governments and practitioners about case studies and the latest advances in the state-of-the-practice. Developed by Passion for Action (a Surrey company) Page 2

3 Natural State Natural State shows the conditions of the area before any development has taken place. Traditional Development Traditional development shows a typical house built in the past before sustainable practices have taken place. This might be representative of the typical homes in your neighbourhood that are older. Sustainable Development Sustainable development has been implemented with new development areas. Typically these include newer subdivisions where entire infrastructures are developed at the same time. This might be representative of homes and neighbourhoods that are newer. Developed by Passion for Action (a Surrey company) Page 3

4 Natural State - after a short light rain 1. Trees intercept rain and absorb water from the ground. Water gets trapped by the leaves, the branches and even the tree trunk. Sometimes very little water makes it to the ground. 2. Existing topsoil and ground plants hold water like a sponge or let the water flow down through to the soil below recharging the ground water. Water may runoff if it can not soak in fast enough. 3. Subsoil stores water for use by plant roots. Surface water may start to fill the subsoil. 4. Surface water starts to runoff and may be absorbed into the topsoil. Excess groundwater seeps towards the creeks and lakes. 5. Small amounts of water make it to the creek. Creek levels may rise due to rainfall close to the banks of the creek. Natural State - after a long light rain 1. Trees intercept rain absorbing, and slowing down the water reaching the ground. 2. The topsoil fills with water and stores it until it can soak deeper into the ground. Ground plants slow water that flows along the surface preventing the topsoil from washing away. 3. Subsoil gets saturated, stores water or soaks it deeper into the ground. Provides long term source of water for plants and creeks. 4. Surface flows start and drain towards creeks and lakes. 5. Surface flows may make it to creeks and lakes. Clean cool water seeps in from the surrounding soil feeding the creeks for days to come. Developed by Passion for Action (a Surrey company) Page 4

5 Natural State - after a short heavy rain 1. Trees intercept rain and absorb water from the ground. Water gets trapped by the leaves, the branches and even the tree trunk. Sometimes very little water makes it to the ground. 2. Existing topsoil and ground plants hold water like a sponge or let the water flow down through to the soil below recharging the ground water. Water may runoff if it can not soak in fast enough. 3. Subsoil stores water for use by plant roots. Surface water may start to fill the subsoil. 4. Surface water starts to runoff and may be absorbed into the topsoil. Excess groundwater seeps towards the creeks and lakes. 5. Small amounts of water make it to the creek. Creek levels may rise due to rainfall close to the banks of the creek. Natural State - after a long heavy rain 1. Trees intercept rain. Excess rain makes it to the ground. Trees help reduce and resist erosion. 2. The topsoil fills with water allowing it to soak into the ground. Excess water flows along the surface. Ground plants slow water that flows along the surface preventing the topsoil from washing away. 3. Subsoil gets saturated. Over time the water will soak in deeper, or flow towards low areas such as creeks. Stored water provides long term supply of moisture for larger plants. 4. Surface flows form channels and ditches. Topsoil and subsurface water may seep out and flow over the surface towards creeks and lakes. 5. Creek levels rise and flows increase during and following the rain. Flooding may occur. Clean cool water seeps in from the surrounding soil feeding the creeks for days to come. Developed by Passion for Action (a Surrey company) Page 5

6 Traditional Development - after a short light rain 1. Connected Drain Spouts - Water runs directly from the roof to the storm sewer. 2. Thin top soil retains rain water from a light rain. 3. Storm sewers efficiently collect all runoff directing it to the outfall. 4. Little or no water from a light rain reaches the creek. Traditional Development - after a long light rain 1. Connected Drain Spouts - Water runs directly from the roof to the storm sewer. 2. Thin top soil - Once saturated, allows water to flow directly to the street. A small amount of water is able to soak deeper into the ground before the topsoil dries out. 3. Storm sewers efficiently collect all runoff directing it to the outfall. 4. Water flow in the creek increases quickly as the water discharges from the storm sewer and falls shortly after the rain stops. Flooding may occur. Developed by Passion for Action (a Surrey company) Page 6

7 Traditional Development - after a short heavy rain 1. Connected Drain Spouts - Water runs directly from the roof to the storm sewer. 2. Thin top soil - Once saturated, allows water to flow directly to the street. A small amount of water is able to soak deeper into the ground before the topsoil dries out. 3. Storm sewers efficiently collect all runoff directing it to the outfall. 4. Flow rates at outfalls may be high causing local erosion. Total runoff may not cause increased flows in creeks. Short duration flooding may occur. Traditional Development - after a long heavy rain 1. Connected Drain Spouts - Water runs directly from the roof to the storm sewer. 2. Thin top soil - Once saturated, allows water to flow directly to the street. A small amount of water is able to soak deeper into the ground before the topsoil dries out. 3. Storm sewers efficiently collect all runoff directing it to the outfall. 4. Water flow in the creek increases quickly as the water discharges from the storm sewer and falls shortly after the rain stops. Flooding may occur. Developed by Passion for Action (a Surrey company) Page 7

8 Sustainable Development - after a short light rain Sustainable Development - after a long light rain 1. Disconnected Drain Spout - Rain water is dispersed through the gravel or topsoil and gradually seeps into the ground. 2. Extra deep top soil soaks up and retains water reducing the amount that reaches the storm sewer, increasing the amount available for plants and soaking into the ground below. 3. Rock pits with lawn drains collect and store water reducing the amount that needs to be drained. 4. Perforated pipes allow some of the water to seep into the soil reducing the amount that needs to be drained. 5. Drainage swales allow rain water from the street to seep into the ground before reaching the storm sewers. 6. Trees drink significant amounts of water reducing the amount of water that needs to be drained. 7. Very little water reaches the holding pond as other sustainable features have delayed the drainage of water. 8. No impact on the creek. Groundwater supplies much of the creeks year round flows. 1. Disconnected Drain Spout - Rain water is dispersed through the gravel or topsoil and gradually seeps into the storm drain or the ground below. 2. Extra deep top soil soaks up and retains water reducing the amount that reaches the storm sewer, increasing the amount available for plants and soaking into the ground below. 3. Rock pits with lawn drains collect and store water reducing the amount that needs to be drained. Excess water soaks into the surrounding ground. 4. Perforated pipes allow some of the water to seep into the soil reducing the amount that needs to be drained. 5. Drainage swales allow rain water from the street to seep into the ground before reaching the storm sewers. 6. Trees drink significant amounts of water reducing the amount of water that needs to be drained. 7. Water reaches the settling pond where it can soak into the ground or evaporate. 8. No impact on the creek. Groundwater supplies much of the creeks year round flows. Developed by Passion for Action (a Surrey company) Page 8

9 Sustainable Development - after a short heavy rain 1. Disconnected Drain Spout - Rain water is dispersed through the gravel or topsoil and gradually seeps into the storm drain or the ground below. 2. Extra deep top soil soaks up and retains water reducing the amount that reaches the storm sewer, increasing the amount available for plants and soaking into the ground below. 3. Rock pits with lawn drains collect and store water reducing the amount that needs to be drained. Excess water soaks into the surrounding ground. 4. Perforated pipes allow some of the water to seep into the soil reducing the amount that needs to be drained. 5. Drainage swales allow rain water from the street to seep into the ground before reaching the storm sewers. 6. Trees drink significant amounts of water reducing the amount of water that needs to be drained. 7. Water reaches the settling pond where it can soak into the ground or evaporate. 8. Potential for flows to the creeks from surface similar to undeveloped conditions. Sustainable Development - after a long heavy rain 1. Disconnected Drain Spout - Rain water begins to pool as ground reaches saturation and water flows along surface. 2. Topsoil is saturated excess runs off towards the sidewalk. 3. Rock pit fills and the excess water flows into the storm sewer. 4. Perforated pipes allow some of the water to seep into the soil reducing the amount that needs to be drained. 5. Drainage swales overflow as subsurface gets saturated. 6. Trees drink significant amounts of water reducing the amount of water that needs to be drained. 7. Water reaches the settling pond where it can soak into the ground or evaporate. The ponds provide a buffer for flows to the creek. 8. Creek Floods on long heavy rainfall similar to undeveloped conditions and long term water flows are provided by groundwater. Developed by Passion for Action (a Surrey company) Page 9