Welcome to Proper Maintenance of

Transcription

1 Welcome to Proper Maintenance of Stormwater Management Facilities [SMF] May 17, 2006 Repp Glaettli This presentation was designed for owners and maintainers of stormwater management facilities. The background image in this slide is a photograph of Birnam Basin, a County regional stormwater management facility. 1

2 Main Topics Stormwater Background Applicable County Code Water Quality and Erosion Long-term Maintenance and Costs This presentation covers: County Codes that are important to stormwater facilities How to improve the quality of stormwater Ways to manage for long-term maintenance and associated costs 2

3 Basics of Stormwater Stormwater = Runoff from Precipitation Stormwater travels from Streets to Streams Urban Runoff Carries Excess Volume Urban Runoff Carries Pollutants Stormwater and stormwater management are overlooked by the general public. Stormwater is important to all of us because it enters our streams and then provides drinking water for our neighbors and aquatic life. Stormwater Defined: precipitation that hits the earth s surface and runs off When land is developed, stormwater enters our streams at higher and faster concentrations, which leads to erosion. Stormwater Management Facilities are designed to slow the stormwater. Slowing stormwater helps to reduce erosion. Originally, stormwater was only treated for quantity and speed. Stormwater is now beginning to be treated for pollutants that are picked up as the water traverses parking lots, streets and driveways. The county has begun to require pollutant-absorbing vegetation in our newly approved Stormwater Management Plans. 3

4 History of County Stormwater 1979: 1 st Engineered Facility Constructed 2006: 350+ Facilities The study of stormwater is a relatively new field when applied to developing in our region just over 30 years old. The first documented stormwater management facility in Albemarle County was created in the late 1970 s as an experimental project by UVA. There are now well over 350 stormwater management facilities needing inspections yearly in the county. 4

5 Who currently conducts inspections? Sec : Inspections. Part B The program authority (Stormwater Inspector) How often are inspections performed? Sec : Inspections. Part B Inspection shall be conducted at least annually to determine whether measure comply with approved plan or Investigate a complaint pertaining to the plan Question: Who inspects all of these facilities and how often? Answer: The County Code gives the directive that the stormwater management facilities will be inspected by the program authority or assignee (currently, the Storm Water Inspector) at least once a year or in response to a complaint. 5

6 Why should facility owners conduct regular inspections? Answers: 2 Reasons 1. Regular inspections keep your costs down Blown-out Detention Basin Dam There are two main reasons owners of stormwater management facilities should conduct inspections of their own facilities. The first reason is to make sure the facility has not been damaged after a recent rain storm. Small problems can quickly escalate to large, expensive, and sometimes dangerous problems. 6

7 2. Your Maintenance Agreement states: Section 3. The Landowner, its successor and assigns, shall inspect the stormwater management/bmp facility and submit an inspection report annually. (currently not enforced) The second reason is that many of you have Maintenance Agreements that state you shall inspect the stormwater facility at least annually. However, we are currently not enforcing this element of the Maintenance Agreement. This could change in the future, at which time you will be conducting the inspections on your own. These inspections are not difficult or complex. Inspection sheets are available at: 1. Click on Form Center in the sage-colored strip in the middle of the page 2. On the drop down menu click Design Standards Manual 3. Scroll down to Select a form below: and click Design_Standards_Manual_Chapter05_Water_Resources.pdf 4. Inspection sheets are found on page 107 to page 112 7

8 Inspection Procedure. Detention Basin Dam was Breached due to Clogged Pipes Many stormwater facilities have pipes that need to be maintained. The most important common practice inspection you can conduct is make sure pipes are not clogged. This will help reduce the breaching of dams as seen in this picture. The corrugated metal (CMP) riser pipe, or stand pipe, was clogged or damaged, keeping the water from properly draining out of the basin. As a result, the water over-topped and then breached the dam. 8

9 Why do I have to maintain my facility? Albemarle County Code Sec : Duty to comply, maintain and repair; maintenance. 1. comply with all of the terms and conditions of the approved plan 2. maintain and repair all structural and nonstructural stormwater management measures required by the plan, as provided herein: (see page 17-34) If problems are found with your facility, the County Code states that you are responsible for making necessary repairs. The rest of the Water Resources Division and I will be glad help you in any way that we can, however we do not currently offer funding. 9

10 How facility owners can protect water quality and prevent erosion. Pick up trash regularly Mow SMF twice a year Fertilize private lawns in the Fall Re-plant bare areas Plant natives or non-invasive plants Next, we will go over ways to strengthen your facility s effectiveness. If you follow some of these practices you will help improve water quality and increase the life of your facility. 10

11 Pick Up Trash Regularly Create neighborhood groups to pick up trash Include trash up in your landscaping contracts Trash can clog pipes and riser structures that are used for emergency overflow. Create neighborhood clean-up groups through your home owners association to pick up trash in your neighborhood and around your stormwater management facility. Another option maybe to require your hired landscaping or property property maintenance company to pick up trash from facilities. 11

12 To Mow or not to Mow Tall Native Grass = long strong roots Woody vegetation not good for Dams Mowing may not always be necessary for a stormwater facility. Many native grasses will provide extra erosion protection if allowed to grow tall, as depicted in the picture on the right. As you can see, over-mowing these non-turf grasses can lead to declining root structure. We strongly discourage allowing woody vegetation on dams. Mowing dams to keep down any woody vegetation is a good idea at certain times of the year. (See next slide.) 12

13 Why Mow only Twice a Year? Most woody vegetation grows up in the Spring Most grass goes to seed in the early Fall If you do plan to mow your stormwater management facility, we recommend that you do not mow it more than twice a year. Woody vegetation, like trees and shrubs, send up sprouts in the spring that are easily mowed in early spring. Most native grasses go to seed in fall, so mowing too early in fall will destroy your crop of native grasses for next spring. 13

14 When do I Mow? First mowing should be: March or Early April Second Mowing should be a week after first frost: October or November IF YOU ONLY MOW ONCE A YEAR: March or Early April You should schedule mowing of Stormwater Facilities for March and late October. Alternative months to mow are early April and November. The most ideal time to mow is once a year in March. 14

15 Fertilize Home Lawns in the Fall Home Lawns are believed to be one of the largest contributors of pollutants entering the Chesapeake Bay For further information on lawn care go to Over-fertilization causes damage to the health of our rivers and bay. The image of this retention basin, wet pond, above, shows signs of overfertilization because of the algae present. The nutrients found in fertilizers can cause algae blooms, if the fertilizers are washed into our waterways. When algae dies, oxygen is reduced, and most aquatic animals will die without oxygen. We are promoting fertilization in the Fall to promote root growth and a healthy lawn year round. Fertilization in the spring promotes greater shoot growth and results in needing to mow your yard more frequently. The Chesapeake Club has some very helpful tips on taking care of your lawn. The website is available in the slide. 15

16 Re-planting bare areas Drought tolerant Erosion resistant Mix Grass and Forbs a.k.a. herbs Use Native plants or non-invasive If vegetation is missing in a stormwater facility we do require that you re-plant the facility with vegetation. Not all plants are created equal. To reduce your costs and watering needs, install drought tolerant and erosion resistant vegetation. This type of plant is usually a native species and is usually not turf grass. In may cases, this type vegetation that is drought tolerant and erosion resistant grows naturally in surrounding un-kept areas. Many people refer to this type of vegetation as weeds. These weeds are your best source for native plants. Just make sure you do not over harvest them. Another option for low profile vegetation, such as turf grass, is forbs (aka: wildflowers, herbs, weeds). Once established, forbs do not require the high maintenance associated with turf grasses and make excellent groundcover. There are some short growing varieties that grow in this region, make sure when planting any vegetation that the location drives the type of vegetation needed. Plants require different light, water, soil and nutrient needs. 16

17 Plant native or non-invasive plants Resources: Grasses, Sedges, wildflowers plants.usda.gov/ For more information on native plants and their growing conditions, please check out the websites in the slide. In the near future we will have links to these site on albemarle.org 17

18 How to Plan for Long-term Maintenance Needs. Identify type of SMF you have? Identify needs of your SMF? Create savings account. Reduce amount of Stormwater entering SMF. Regular maintenance prevents long-term problems. The following slides are a starting point for addressing long-term maintenance needs and costs. 18

19 Identify type Your Facility Type Residential: Biofilter/ rain garden Retention Basin (wet pond) Detention Basin (dry pond) Level Spreader Water Quality Swale Commercial: Filterra Stormceptor Sand Filter Underground Storage (large pipe underground) The first thing you need to do as a stormwater facility owner is to review you stormwater management plan. Your approved stormwater management plan shows how the facility was originally constructed and how it should be maintained. Stormwater management plans are usually one component of a site plan. To request a stormwater management plan from the County, contact the Community Development department at (434) and ask for your development s or subdivision s approved site plan. Within the site plan there will be a page with your stormwater management plan and sometimes there will be a separate page(s) for details. 19

20 Identify needs of your SMF. Vegetation established? CMP vs. RCP Stand pipes Holding water: good or bad? Water color? Rip Rap not Repp s Rap for SMF You will then need to find out the most common needs of your facility, so that you can develop a good long term maintenance plan for your facility. The picture on the right shows a CMP riser structure. CMP stands for Corrugated Metal Pipe. This type of pipe needs to be replaced about every 20 years. The picture on the left shows an outfall of a pipe with no rock (rip rap) to slow down the flow of water. More rock needs to be added at the end of the pipe according to the County Design Standard Manual. 20

21 Create Savings Account Estimates General savings per year $1,000 per small Stormwater Management Facility (Will vary) Rebuilding small Detention basin $15,000 Clean small lake/ forebay (3 days with Vacuum-truck) Vac-truck per day: $2,500-4,000 Dredging large lake: $1 million dollars Start a savings account now for your Stormwater Facility. The amount you need to save does vary between facilities. This slide shows estimates of common repair costs. 21

22 DECREASE the amount of Stormwater entering SMF. Plant more trees to uptake water/ slow flow of water Allow Grass to be maintained Higher: Raise the level of the deck on movers Install Rain Barrel or Cisterns Add small non-inspected Rain Gardens Retro-fit with porous pavement Add green roofs (using grants?) The less use your facility gets, the longer it will last. This slide shows a couple of ways of reducing the amount of water entering into your facility. 22

23 DECREASE Pollution flowing to Stormwater Facilities Fertilize lawns in the Fall Pick up pet waste Install Rain Gardens in your yard Clean out septic tanks Vegetation can only uptake so many pollutants. Practice these alternatives instead of allowing as much pollution to enter into your Stormwater Facility. For further information on steps you can personally take to improve the water quality leaving your property, please take a look at Martin Johnson s PowerPoint presentation, Rain, Runoff, and your Backyard. 23

24 ? Contact info: Repp Glaettli If you any questions regarding this presentation please do not hesitate to contact us in the Water Resources Division. Contact information is included in this slide. 24