NaSBAP Unit Questions (at end of each Unit) Unit 6 – Site / Water

  • 1. Explain the natural and anthropogenic (human-caused) reasons why fresh water is scarce on our planet. (PG: 6-16)
  • Unpolluted surface water sources, or ones that can be treated to drinking water standards (potable), are difficult to find, manage and protect; and treating that water to drinking water quality is energy-intensive & expensive.
  • Bulk of planet’s water is stored in sea water = 95%
  • Vast majority of fresh water is located in Canada, US and Russia
  • Unpolluted water sources can be treated to drinking water standards; treating water is energy-intensive and expensive
  • 0.6% = world’s fresh water for use in form of rain, lakes and groundwater
  • Critical in understanding local water resources is identifying its watershed, or the area that drains rainwater, melting snow and other sediment and materials downhill into specific basin of streams, rivers and lakes.

2. Define the following: (PG: 8)

  • Rainwater – roof or clean source run-off
  • Stormwater – rainwater run-off from site hardscapes
  • Graywater – “used” water from sinks, showers and laundry
  • Blackwater – “Used” water from toilets
  • Combined water – black water and grey water
  • Reclaimed water – water treated and sold for reuse by wastewater treatment plants

3. How is infiltration and runoff different in a metropolitan area versus a native, forested area? What are the impacts?

  • Forested areas: trees purify our air, help infiltrate storm water, shade from the sun, and create habitat for many species important to a healthy ecosystem = higher evapo-transpiration (ET) more water penetrates the ground. Native forests return an average of 40% (water) to the sky through ET, and infiltrates more than 35% to the soil, so little (+/-15%) of stormwater runs off.
  • Metro areas: infiltration happens less due to poor infiltration because of houses, pavement, concrete, asphalt due to its impervious nature = lower evapo-transpiration (ET) less water penetrates the ground. Suburban developments return an average of 30% (water) through ET, and infiltrates less than 16%, so the majority (+/-54%) of stormwater runs off.

o Impacts: increased runoff and heat transfer from hard surfaces in developed areas result in higher peak flows in streams, which causes increased stream bank erosion (fewer pools), sedimentation (smothers aquatic life), higher water temperatures in summer, flood damage to property.
o Faster storm runoff in developed areas and less rainwater infiltration into soil fail to recharge groundwater resources and can cause lower dry season flows in small streams, greater degrees of turbidity and pollution, shallower water, significant stress to fish populations, imbalances between groundwater withdrawals for water use and the rate of aquifer recharge.
o Negative impacts: degradation and lost of soils once protected by trees.
o Decreased slope stability.
o Decreased large woody debris (LWD) which provides shade and native food sources for stream life, including salmonids.
o Increased peak storm runoff in summer and colder in winter, resulting in increased heating and cooling costs and, ultimately, energy use.

 

4. Define point-source and non-point source pollution, and provide an example of each. (PG: 17-19)

  • Point-source pollution (PSP): consists of pollutants discharged from a single, identifiable, localized source.

o Since 1972 the Clean Water Act (CWA) has governed and regulated the discharge of point-source pollutions from industrial, municipal and some agricultural sources in the US. Example, discharge pipe from manufacturer’s plant.
o The National Pollutant Discharge Elimination System (NPDES) permitting program regulates & monitors point source pollution from industrial process waters, publicly-owned treatment works, and municipal & industrial stormwater. Since the enactment of the CWA & NPDES program, pollution discharged by domestic facilities has decrease by 70%, while the amount of wastewater treated has increased 70%.

  • Non-point-source pollution (NPS): this pollution comes from many diffuse sources, such as uncollected pet waste in parks and city streets or chemicals from conventional landscape products that run off the property, and is caused by runoff from rainfall or snowmelt picking up and carrying both natural and man-made pollutants over and through the ground.

o Common sources of pollution: fertilizer (lawn and garden) have high levels of phosphorous and found in surface waters. These run off the surfaces and disturbed soils promoting algae blooms that then decompose and deplete oxygen needed by fish and other aquatic life.
o Pesticide pollution: weed, systemic herbicides and insecticides. Pesticides remain in lawns and are tracked into homes
o Chlorine and fluoride – these can mix with other chemicals in water and impact plants, animals, and humans; can degrade IAQ especially when heated.

5. What are the (6) strategies of the ‘Nature as Model’ approach? (PG: 21)

  • Strategies are based in science and field experience
  • Meet user’s functional needs while transforming current aesthetic standards
  • Are cost –effective in long run (considering all costs and resources limits)
  • Make efficient use of natural processes
  • Have significantly lower adverse impacts
  • Ideally, have multiple benefits
  • Natural Systems Model (Living Building Challenge seeks to meet most of the below):

o Everything is recycled endlessly (water, waste and nutrients)
o Landscape diversity provides dynamic stability
o Systems are defined by the natural resources available on-site
o Landscapes have inherent beauty, elegance, complexity and balance

6. What is the progression of (4) design goals for sustainable site development? (PG: 27)

  • Conventional development: addresses human safety, major problems and disasters
  • Low Impact Development (LID): reduces negative impacts on resources
  • Sustainable (Zero Impact) Development: maintains and conserves resources
  • Regenerative (Restorative) Development: restores damaged resources

7. Define LID and identify examples of LID strategies and features. (PG: 29)

  1. Low Impact Development (LID) is a cost-effective alternative stormwater-control technology. LID’s goal is to reduce development impacts to better replicate natural watershed hydrology. LID controls runoff discharge, volume, frequency, and quality to mimic predevelopment runoff conditions.
  • Efficient Site Design – will minimize the amount of pervious area on the site. Methods include clustering buildings, reducing building size to smaller footprints, reduced street widths, shared parking and driveways. Sustainable site development patterns feature increased density or clustering, allowing more open space. LID patterns and practices compliments clustering and promote more natural functionality of such sites.
  • Permeable pavements – are porous paving surfaces designed and built with a high void ratio to allow water to flow through, or permeate the surface. Examples: pervious concrete or asphalt pavement, interlocking concrete pavers, gravel or grass cellular confinement systems, reinforced grass surfaces
  • Soil amendments – amending soil with compost is a technique that can transform degraded soils to healthy, fertile soils in a relatively short period. Nourishes plants to resist disease and drought, absorb, break down pollutants and restore water to clean state.
  • Vegetated or Green Roofs – a space on top of a human-made structure. Green roofs provide a variety of environmental and social benefits including storm water management, more habitat, longer roof life and reduced cooling loads.
  • Bioretention (rain gardens and swales) – this is an integrated storm water management practice that mimics natural hydrology by using the physical properties of plants, microbes and soils to infiltrate storm water and remove pollutants.
  • Rainwater collection and Reuse – rainwater harvesting from roofs and storing it later for future use. System components include conveyance, filtration and pump. Water reuse means capturing and filtering water that is normally sent down the line as “waste” to reuse again.
  • Conservation / Protection – is an existing, quietly effective LID technique that involves the preservation and protection of native vegetation and soil.
  • Disconnect While Reducing Impervious Surfaces – Disconnecting roof downspouts from public storm or sewer systems minimizes the amount of stormwater a municipality has to manage. Reducing impervious surfaces also has the same effect.

8. What is the hierarchy of best management practices (BMPs) for native soil protection and conservation? How is this different from conventional practices? (PG: 34)

  • Best choice: do not disturb native soils – leave the native soil in place and protect it from compaction and erosion during construction
  • Next choice: if soils must be disturbed, try to limit soil disturbance to as small an area as possible. Move the soils elsewhere, store and protect them during construction, and then replace the soils on the site, in reverse order from how they were removed, once construction is complete.
  • Third choice: Restore removed soils with compost. When topsoils are removed and not replaced, the result is compacted subsoil with minimal organic matter. Amending by tilling in compost will improve the soil health.

9. What roles do trees play in both sustainable landscaping and on a larger more global scale? (PG:36-38)

  • Trees take in carbon dioxide and respire oxygen. So preserving and planting trees is an important carbon sequestering strategy. By respiring oxygen, trees also help dilute the concentration of other greenhouse gasses.
  • Trees provide tangible services in urban areas such as privacy, noise control, temperature buffering, which leads to AC savings, smog reduction and particulate filtering
  • Trees take in and filter and slowly release large volumes of water.
  • Trees in sustainable environment can be a cost-effective water-quality improvement option. This is a fundamental strategy of LID.

10. Describe the purpose and benefits of mulch and compost in a sustainable landscape. (PG:35)

  • Mulch is aesthetic in appearance and will have slow release organic nutrients to enrich the soil as blending favorably with the various hues of the foliage; fights weeds, insulates soil (holds temperature better) and helps with moisture retention, when it breaks down it introduces valuable organic materials into the soil.
  • Compost aerates soil and increases water-holding capacity.

11. Which indoor commercial and residential equipment reduces water consumption and are “low hanging fruit” in terms of implementation ease and payback? (PG: 49-52)

  • Showerheads – install low-flow to give quick payback (2-2.5 gallons per minute (gpm)
  • Faucets & aerators – install low-flow to give quick payback
  • Toilets – account for btwn 25-50% of household water use.
  • Urinals – waterless
  • Washers – Energy Star washing machines which use at least 20% less water

o Water Factor (WF) – number of gallons needed for each cubic foot of laundry.
o Baseline WF = 13.3, most efficient WF = 7.5

  • Dishwashers – Energy & Water efficient machines use 0.28-1.2 gallons per rack.
  • Dishwasher Pre-Rinse Spray Valves – Efficient models use 1.2-1.6 gpm.

Which might require more challenges or upfront cost?

12. What are the steps in a water audit? (PG: 56-58)

  • Identify leaks by reviewing utility bills
  • Read the water meter
  • Systematically analyze high-water use equipment – once its determined the meter is running is running during times of no use, investigate the following:

o Tank style toilets – flappers on these toilets sometimes wear out and the seal is no longer solid
o Irrigation systems – look for obvious surface leaks

  • Commissioning (Cx) – water system commissioning includes testing building equipment to ensure that its operation meets the design specification and does not exceed the level of water use required by code and building design guidelines.

13. List examples of conventional on-site wastewater treatment and sustainable on-site wastewater treatment. (PG: 59-60)

  • (4 Types) Conventional on-site wastewater treatment:

o Aerobic treatment unit (ATU) – used as pretreatment, an ATU adds air to break down organic matter, reduce pathogens, and transform nutrients
o Recirculating Sand Filter (RSF)– uses a sand filter to reduce pollutants, including suspended solids …. It minimizes the likelihood of a drainage field to become clogged.
o Mound system – are elevated absorption beds that use suitable sand filler to partially treat wastewater before it reaches native soil.
o Septic system – tank holds wastewater long enough for solids, oil, and grease to settle out and form sludge or scum, which is periodically pumped out as part of septic system maintenance.

  • (3Types) Sustainable on-site wastewater treatment

o Subsurface flow constructed wetlands – as water travels through the wetland, sand filters out particles and microorganisms break down organic matter. Pre-treatment is usually required to prevent clogging.
o Ecological wastewater treatment and reuse system (Living Machine) – is a biological treatment system for water that uses aquatic and wetland plants, bacteria and other organisms to clean and treat waterborne pollutants in black or gray water.
o Algal systems – the algae mat system uses a combination of algae and bacteria to clean and treat wastewater. The algal growth, through the process of photosynthesis, produces oxygen and consumes carbon dioxide naturally.

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