Overview:
A possible method for schools to capture excess water to use in their garden is with a rainwater harvesting system.
[1]
Rainwater harvesting systems usually begin with a “catchment” surface like a roof. The rain collects and goes through a filter. Pipes can then deliver rain to storage tanks. From storage, water can be run to hoses, toilets, ponds, irrigation systems, and gardens [2].
This is an example of how a rainwater harvesting system at a house may work, however, this will probably not be exactly similar to what students will be implementing at their school. Since schools will likely be much larger than a house and schools may not want their rainwater collection system to expand all across the school building, the system may end up having to be more limited to only the roof and a small portion of the school.
Precipitation Data:
One con of implementing a rainwater harvesting system is that rainwater will likely not be a reliable or constant source of water since the amount of rain different regions in the Navajo Nation get every year can vary.
While there is not a lot of data from rain gauges in the Navajo Nation for specific years, there were data for rain precipitation in the Gallup Municipal Airport, a place located around 25 miles from Window Rock (the capital of the Navajo Nation).
Daily Precipitation in 2021 at Gallup Municipal Airport
[3]
Daily Precipitation in 2020 at Gallup Municipal Airport
[4]
Daily Precipitation in 2019 at Gallup Municipal Airport
[5]
Just from observing the rainfall over a period of 3 years (from 2021 to 2019), one can see that the amount of rain Gallup Municipal Airport receives is not consistent. In some years (2021 and 2020) the area may receive a lot of rain in the summer months and not a lot for the rest of the year, while in another year (2019) it may receive a lot of precipitation consistently throughout the year.
Caption: Map showing the annual precipitation over the Navajo Nation during the last 40 years. Note that the Nation receives very little rainfall compared to the surrounding areas, and that there has generally been a downward trend in the amount of precipitation received over time.
Precipitation data from [6], State/County/Navajo Nation boundaries from [7].
The figure above shows how the annual precipitation in the Navajo Nation changes from 1981 – 2021 based on estimated average rainfall from existing rain gauges and satellite observations [8]. From the continuously varying color intensity in the map, it is apparent again how inconsistent the amount of rainfall the Navajo Nation receives from year to year is.
Example of Rainwater Collection:
In 2019, two Diné sheepherders, Arvin Bedonie and Marie Gladue, in Black Mesa, Arizona started to harvest rain as an alternate water source. While in the past few years the summers have been more dry than usual, when there was rain, they were able to capture around 200 gallons per inch of rain [2]. On average, the Navajo Nation gets around 1 inch of rain each month from July to September [9], meaning in those three months Bedonie and Gladue would get roughly 200 gallons a month. Residents of the Navajo Nation use 7 gallons of water on average [10] meaning the water Bedonie and Gladue capture from rainfall over one month could ideally help support them for over 28 days.
While the rainwater would need to be harvested and filtered properly to be used as potable water for humans, the water could be given to livestock, used to flush toilets, or water gardens. Having rainwater as an additional source of water would decrease the reliance on drinking water for other purposes.
Implementation of the System:
Since schools in the Navajo Nation may have various unique roof constructions, schools may want to set up their rainwater collecting system in different ways. If a school already has a gutter system, they may simply want to install an extension system to connect their gutter to a water storage container. Otherwise, they may want to run new pipes across their roof that will collect water and deliver it into a storage container.
Since the water would be used mostly to water the garden and not as potable water, the filtration system would not need to be very complex. To remove large contaminates from the water, schools may want to use a metal mesh. These can be attached to the end of the pipes or fittings and above the storage container. Schools may also want to put a gutter strainer in the opening of the gutter on the roof to prevent large objects from blocking the pipes [11].
To store the water, a possible option for schools to consider is the RainFlo Eco School Basic Package. This is a complete package designed to introduce students to rainwater collection systems. It comes with a hose bibb that allows for easy connection to a hose with which the students can use to water their garden [12]. Since hardware stores may be difficult to access in the Navajo Nation, having all the necessary supplies for storage and usage in one package may help schools start collecting rainwater with more ease.
Educating students about rainwater collection systems can help increase self-sufficiency and decrease reliance on drinking water for agriculture.
Cost:
The total cost of the system would depend on how each school may want to design their collection system. However, an estimation of the cost would include the metal mesh ($20), a cutter strainer ($5), a gutter extension system ($13), and the RainFlo collection system ($800) for a total of about ($838).
Works Cited:
[1] ByJus. (2020). Rainwater Harvesting -Process, Advantages and Disadvantages. BYJUS. https://byjus.com/biology/rainwater-harvesting/.
[2] Malloy, C. (2020, December 7). Millions of Americans lack access to running water. An ancient method of capturing rainwater could help solve this. The Counter. https://thecounter.org/ancient-rainwater-harvest-technology-used-for-access-to-water-supply-navajo-nation/.
[3] 2021 Past Weather at Gallup Municipal Airport, New Mexico, United States – Weather Spark. (n.d.). Weatherspark.com. https://weatherspark.com/h/y/145581/2021/Historical-Weather-during-2021-at-Gallup-Municipal-Airport-New-Mexico-United-States#Figures-Rainfall.
[4] 2020 Past Weather at Gallup Municipal Airport, New Mexico, United States – Weather Spark. (n.d.). Weatherspark.com. https://weatherspark.com/h/y/145581/2020/Historical-Weather-during-2020-at-Gallup-Municipal-Airport-New-Mexico-United-States#Figures-Rainfall.
[5] 2019 Past Weather at Gallup Municipal Airport, New Mexico, United States – Weather Spark. (n.d.). Weatherspark.com. https://weatherspark.com/h/y/145581/2019/Historical-Weather-during-2019-at-Gallup-Municipal-Airport-New-Mexico-United-States#Figures-Rainfall.
[6] Funk, C., Peterson, P., Landsfeld, M., Pedreros, D., Verdin, J., Shukla, S., Husak, G., Rowland, J., Harrison, L., Hoell, A., & Michaelsen, J. (2015, December 8). The climate hazards infrared precipitation with stations-A new environmental record for monitoring extremes. Nature News. https://www.nature.com/articles/sdata201566.
[7] U.S. Census Bureau (2022). TIGER/Line Shapefiles. https://www.census.gov/geographies/mapping-files/time-series/geo/tiger-line-file.html.
[8] CHIRPS: Rainfall Estimates from Rain Gauge and Satellite Observations | Climate Hazards Center – UC Santa Barbara. (n.d.). Chc.ucsb.edu. https://chc.ucsb.edu/data/chirps.
[9] Navajo Climate, Weather By Month, Average Temperature (New Mexico, United States) – Weather Spark. (n.d.). Weatherspark.com. Retrieved December 1, 2022, from https://weatherspark.com/y/3005/Average-Weather-in-Navajo-New-Mexico-United-States-Year-Round.
[10] Morales, L. (2015, January 6). For Many Navajo, A Visit From The “Water Lady” Is A Refreshing Sight. NPR.org. https://www.npr.org/sections/codeswitch/2015/01/06/374584452/for-many-of-navajo-nation-water-delivery-comes-monthly.
[11] Bliss, D. (2011). How To Build A Rainwater Collection System. In www.youtube.com. https://www.youtube.com/watch?v=MYTNciCplmw&ab_channel=DecoBliss
[12] RainFlo Eco School Basic Package – Rainwater Collection and Stormwater Management. (n.d.). Www.rainharvest.com. https://www.rainharvest.com/rainflo-eco-school-basic-package.asp.