Determining your flood risk

With all the recent flooding happening both in the Midwest and regionally (due to recent wildfires), now seems like a good time to talk about the flood potential of where you live in the desert southwest.  When you live in the desert, most people don’t think much about flood preparation.  However, there are times when it can flood severely, typically in a floodplain like anywhere else. There is a second type of flooding that can affect more people – that of sheet flooding.  Sheet flooding is when enough rain falls on a gentle slope that it no longer sinks into the soil, but moves downhill.  This type of flooding can still build up a decent depth, and I am planning for six inches max on my property near the house(I do like to over prepare). 

When determining what potential flooding may happen on your land, there are several factors you must consider. 

1.       What is the lay of the land? Is it flat, in a depression or hill top, or on a slope?  Check your local city or county maps or codes to determine if you are in a known floodplain.  If you find you are outside of a floodplain, you may still want to look at your topography to determine if sheet flooding or large ponding may affect you.

2.       What is your soil like? Sandy soil will drain much faster than clay soil.  This difference can easily determine the flood potential of your land.

3.       What are the average rainfall and the historic greatest rainfall, especially in a shorter period of time, for your area?  I am rural, and I don’t have exact numbers for rainfall in my area.  I know Tucson averages around 12 inches a year, and that is a good start, but there are other ways of figuring my area out, as I will show you.

Ok, so you have these questions.  How do you find the answers?  As I stated earlier, you might find some relevant information from your city, town, or county land use maps and other related local websites and agencies.  However, if these are not available to you, than there are other governmental entities that can help.  For topography, you can explore your area or get a topo map from the USGS.  Getting a general lay of the land will help you understand the potential of water entering your site from the surrounding land.  To get a better understanding of all three questions, a great website is the NRCS website at http://soils.usda.gov/.  Click on the soil survey tab at the top and then the web soil survey link.  This site is a bit technical and difficult to run on some computers, but it will give you some of the best information out there.  If you are unable to use this site, think creatively.  Yes you can hire a firm to get you all the information you want, or you can save some money and hire a student in the geology, landscape architecture, or planning departments at a local college to look up this website for you.  Another website I use and is good for southwestern climate is from the Western Regional Climate Center at http://www.wrcc.dri.edu/ ; look at the historical information.

All of this information so far can only help you so much.  If you are like most people, a good example will go far in helping you understand things.  To this end, and because this blog is about where I live, I will use my property as an example. 

Lay of the land.  From looking out my window and from exploring the area, I can tell there is a general slope from east to west (Fig. 1).  I also know that immediately around me as well as at the larger scale, the topography is gently rolling with braided washes of various widths and depths weaving their way downslope.  I also know from my observations and from Google Earth that there is a slight hill to my east south east.  The hill blocks views of houses I know are there in the distance and the earth image confirms it with the darker lines created by denser vegetation at washes leading away from a central area (Fig. 2).  On the property, I have watched how water runs during rain to get a good idea of how the water flows across my landscape.  This information I than transferred to a drawing; (Fig. 3) a computer drawing in my case, but it could be hand drawn just as easily. 

So now I have the general lay of the land, let’s move on to the soils.  Again I know from experience through digging that I generally have loamy soils with lots of rocks.  Sandy areas exist in the washes and there are some areas of clay.  But more information would make me feel better, especially as the NRCS analysis will tell me of the greater picture surrounding me.  So what does this analysis tell me?  It tells me I live in the Bucklebar-Hayhook complex (a complex is two or more soils intricately mixed) with 1% to 10% slopes.  In general, these soil types are found from 2090 to 2990 foot elevation with an annual precipitation of 10 to 12 inches of rain.  They are formed on fan terraces and consist of mixed alluvium soil that is mainly sandy loam with some clay loam and are well draining.  The analysis also tells me that the depth to the water table is greater than 80 inches.  This confirms my analysis and expands it to the larger area.  However, I learned more about the rainfall and was reassured that long lasting flooding would not likely happen due to the well draining soil and deep groundwater table.

Finally, the rainfall.  We just learned that there is an average rainfall of 10 to 12 inches for this area.  We also know Tucson averages just over 12 inches.  But I want to know more.  I have kept inconsistent rainfall data in the 12 years I have lived here and found that I average around 10.75 inches of rain.  But if you do not have your own data, you may want to ask your neighbors if anyone has collected information over the years.  Also, if you are rural like I am, I live approximately 25 miles from Tucson; you can look for closer known data.  For me, it is the town of Red Rock found on the Western Regional Climate Center website.  Red Rock averages 9.78 Inches of precipitation a year.  I am upslope and closer to some mountains so I should receive more which aligns with my own tally.

Hopefully this will get you started on informing yourself of the flood potential you have.  Next time, we will look at the strategies I am employing to mitigate my flood potentials.

Fig. 1  North out the kitchen window

The slope flows from east to west and is between 3-7%.  This area is half way down a bajada or alluvial fan slope of the northwest part of the Tortolita Mountains.

 

Fig. 2  Graphic using Google Earth and Photoshop  showing the nearby hill and large scale water flow
You can determine high points on a topographical map or aerial by noting the layout of washes, highlighted here in grey.  The property is the dot on the left and the oval denotes the hill.

Fig. 3  Medium scale of water flow on the property using Google Earth and Photoshop
The larger blue lines show the locations of the current main water channels that flow only during heavier rainfall.  The blue swath is the potential flooded areas associated with the main wash during the most extreme events.  Finally, the smaller arrows show sheet flow with the only threat to the house coming from the drive parking area to the east of the house.

Photo Essay, Spring 2011

Well, this spring has been rather lackluster in wildflowers due to the extreme drought that continues.  However, that doesn't mean there isn't beauty to behold.  So I bring you a brief photo essay of this spring.

Penstemon parryi

Datura meteloides

Echinopsis 'LA' hybrid

Echinopsis 'LA' hybrid

Mesquite

Salvia farinacea

Desert spiny lizard

Wilson's warbler

Gilded flicker

Mourning dove

Beavertail prickly pear

Staghorn cholla

Musings: The desert waits

So it is early June and we continue to be under extreme drought conditions.  I sit on the deck reading a book called the Natural History of the Senses written by Diane Ackerman, listening to a very talkative bird.  The desert spawns small dust devils and the smell of heat vaguely reminds me of the California State Fair.  It is the mingled smells of hot wood and metal, but not so pungent since there is a distinct lack of humanity.  The trees have bloomed and started to set seed, but unlike last year, both are sparse.  Still I partake of some fresh palo verde beans at just the right stage of development.  Fresh palo verde beans are similar to fresh peas.  Both are legumes and I anticipate when I can harvest the dry beans to test cook to see if they can become something like baked beans.  It would be nice to learn how to use what naturally grows here, but I digress a bit. 

The breeze is dry and fairly steady and the one bird talks like a chatty Cathy; it is otherwise silent here.  The bunnies vie for water dripping from a hose, thrashers hop around looking for something to eat, and the trees look like they’re waiting.  They are green with meager fresh growth, but not the lush green that comes with monsoons. The desert is waiting, waiting for the next season-the one of rain and humidity.  The season of distinct temperature changes from the heat of the early day to the sudden cool that comes with the afternoon downpours.  The trees wait, the animals anticipate, and I look forward.

Desert homesteading

There are many ways to be self sufficient, and as time continues, you will see our unique ways of trying to be so.  We live in the very bio-diverse Sonoran Desert on the west facing bajada of the Tortolita Mountains.  What does this mean?  It means that traditional western farming, even small family farming, would not be very successful.  While we have five acres, about a third is occupied by a wash.  That, plus my love for nature and wildlife, limits the room we can use to grow food.  Furthermore, I am the main yardwork/gardener person and I am not the best with machinery, though I can do basic mechanics and use many machines.  I find I prefer handiwork to get things accomplish.  Thankfully, my fiancé John is better with maintenance and operations of the necessary machines we use.  So how can we grow enough to feed two people regularly?  As I just said, we live in the very bio-diverse Sonoran Desert.  That means ALMOST EVERYTHING IS EDIBLE.  So while we plan to grow some common food crops in garden beds (corn, tomatoes, peppers, squash, etc.), I also am familiarizing myself with the many native food crops that grow here naturally.  Some of these foods are: cholla buds, mesquite beans, palo verde beans, prickly pear pads and fruit, saguaro fruit, and several native leafy greens.  Add some traditional perennial crops harvested by the natives before this area was colonized by Europeans, like agave and yucca, and you can add some unique regional flavors to the daily cuisine.  Of course, this doesn’t even include animals.  While we are seriously thinking about adding some chickens, anything bigger is a little more questionable.  But again, nature provides.  We may not have much in the way of large game most hunters are familiar with, but we have numerous quail, cottontail and jack rabbits, javalina,  small varmints, and occasionally deer.  The goal is to live harmoniously within our environment while being as self reliant as possible.  We still have a lot to learn, but I will share this journey with you.

Observations: Spring 2011

This spring has been a good one.  Why do I say this?  It is not because of the spring wildflower show, which hardly happened this year.  It is because the weeds have stayed down and the temperatures keep bouncing back to cooler degrees after short bursts of unseasonable warmth.  Last spring was a great wildflower show, but wildflowers also mean weeds.  The fall and early winter rains that cause good spring wildflower shows did not happen.  So instead, this is the perfect spring to get a lot of yard work done.  Things we have accomplished so far are severe pruning (1/4 to 1/3) off of several mesquite trees, removing cholla, creosote, and bursage out of proposed gathering areas, and the building of two out of nine vegetable garden beds.  The lack of herbaceous weeds and the somewhat normal temps have been a big plus during all of this heavy yard work.

Much of this work has been done in the past; however, it has been a few years since some of the areas have been cleared and they had almost fully grown over with plants.  Since I plan to marry on our property and I now have larger gatherings thanks to John’s large family and many friends, it was time to clean out.  The tree pruning should be done every few years to help shape the trees and remove the weighty new growth.  Now we have gathering areas, camping areas, and shade trees to rest under. 

In conjunction with the clearing, I have put in many hours designing and implementing a kitchen garden south of the house.  I plan to use this not only to grow much of our food, but also to act as a test garden.  Below are some of the pictures and renderings to explain my plans.

Early stages of veggie bed build using reclaimed free brick and homemade compost.

Good luck with your endeavors!   I'll keep you posted with how this all goes.

Apples in the desert

Before we get to the trees, I would like to tell you why fruit trees and why this blog.  I have designs to use my 5 acres to homestead harmoniously within the beautiful desert that surrounds me.  There are many strategies I will employ and you will get to know them through other post further down the line.  It is my hope that others can learn through my experiences, for good or bad, so here it goes.

So now, apple trees in the desert.  You might say, Reeaally?!   But it can be done – with the right varieties.  Most people in the west are probably accustomed to ‘apple hills,” orchards of apples around the 4000’ elevation, usually along the foothills of some mountains.  But there are varieties that can grow in warmer climes.  Here, it is the Anna.  The Anna was born in Israel and is the one to choose in my vicinity at the 2300’ elevation.  Known as one of the apple tree varieties with the least amount of chill required to get fruit, it is often used around here.  A neighbor has had one for over a decade and it does fairly well. 

By the way, that is the best way to find out what tree to plant in your part of the desert – start with successful varieties that are growing around you or at least in a similar climate and microclimate zone.  Jim Koweek, in his book, “Just Add Water,” recommends placing trees in a wind protected area, around here that is on the north-northeast side of the house.  Other trees used as windbreaks can also work.   I have decided to place two Anna’s Apple trees on the north side of my house, on the edge of a side wash – an off shoot of a larger wash to the north, that gets flowing water only in the heavier storms.  This placement is similar to my neighbor’s and should help cooler air flow around the trees in the summer as well as add natural rainwater to the diet.  This probably is not a good idea in most areas, but we are on the warmer end of things, with fewer occurrences of hard freezes.  To help minimize freeze damage, I placed the trees on a bench a foot above the wash.  I will also put large boulders near the trees to act as both bank reinforcements and winter heat islands.  In the spring and summer, mesquite and a desert willow will help shade the area to lessen the heat buildup and act as wind breaks. 

Some information about Anna’s: they are prolific bearers, so thinning is needed.  They are also self fertile, although another variety planted nearby is recommended to make the fruit more round and extend the harvest season.  They also bruise easily, which is why you don’t see them in the store.  Anna’s are crisp, sweet, and slightly tart, and are good all around apples.  Another thing about fruit trees in the desert, they may do well one year and not so well for 2-3.  Still, I would love to have some apples and I am willing to have a few slow years.  Follow along to see how they do.

Cooperation and Respect

It has been a couple days now and the initial shock is over for me regarding the attempted assassination of Gabrielle Giffords, though I still cry on occasion when I think of it.  I still pray for Gabrielle and those affected.  I believe Rep. Giffords to be one of the most reasonable, fully engaged with her constituents congresspeople to grace those halls in many years.  I see this incident more as a way to potentially bring about some restraint on our political leaders in their divisive rhetoric.  The direction of the national media in particular to try to put cause and effect of hate mongering speech with Jared Loughner’s actions, however is missing the point.  Below is my thoughts that I have sent to Diane Sawyer as well as one of our local media stations.  You will not find me speaking on such things often, but this is something I felt compelled to do

I would like to ask that people stop focusing on if fear mongering rhetoric caused Jared Loughner to want to kill Rep. Gabrielle Giffords.  These people are missing the point, whether or not political rhetoric was an influence with him, people are expressing their fear that hate and fear speech is degrading to society and will call the weak minded and unstable people out to do the actions the ‘leaders’ speak of.  There is a great NEED to become a more civilized society, where disagreements can be discussed with respect and solved with some meeting of the minds.  We are all someone’s loved one, we all feel, most participate, and all struggle with something.  Cooperation and respect are the keys needed if this country has a future.

Musings - winter in the desert

John and I recently returned from a trip to my mother's house in the mountains of southern New Mexico and I realized along the drive that I still love my desert the best.  My mom's place is nice as it lies among the pinyon pine/juniper ecological zone with better summer temperatures and minimal snowfall.  But it is quiet.  I mean REALLY quiet.  Where we live in the rural Sonoran Desert, there is just a little sound of humanity, planes, distant trains, and the occasional barking dog or passing vehicle.  But there is bird song, lots and lots of bird songs.  It is not really quite here.  But my mom's place has no sound but the occasional sonic boom from nearby Holloman AFB and a rare vehicle or chainsaw.  It is eerie, hardly ever any animal sounds.  I have thought about moving to her general vicinity, but the cons still outweigh the pros.  Among them are jobs, though I haven't found one in my field of landscape architecture yet, and the fact I own property here that I love.  Part of the draw to stay is the proximity to a medium sized metropolitan area (Tucson), John's ample family, and the fact the desert stays green in the winter time.

Back to my trip home from mom's.  We start in the mountains; go uphill to see the aspens and firs before heading back down to Alamogordo.  This is the nearest town of decent size to my mom's and while I enjoy its small town charms and historic district, it is barren.  There are hardly any trees and many shades of brown.  So onwards we go, through the White Sands of NM to Las Cruces.  This town is closer to the size of Tucson with more trees and the Rio Grande 'flowing' through it.  But it is still many shades of brown.  Further down the road is a repetitive scene of creosote and yucca Chihuahua Desert.  I happen to love these scenes; I am one of those who enjoy geology, ecology, and I still love to look out of the windows in airplanes – but when we finally enter the Tucson area where the Chihuahua Desert transitions to the Sonoran, I light up.  I love the similar geography as found in southern New Mexico (basin and range) but there are trees; trees that stay green in the winter time.  And there is one of the greatest diversity of plants and animals found in the world.  When we arrive at our place, we are greeted with birdsong and running rabbits.  In the winter here, palo verde trees stay green due to their photosynthesizing trunks and colors range from pale greens to reds in the vast variety of plants from various chollas, shrubs like creosote and triangle leaf bursage, columnar cacti like the famous saguaro and the less famous barrel cactus, and six species of trees.  There are dozens of bird species that stay here, as well as cottontails, jack rabbits, antelope squirrel, pack rats and kangaroo rats, many lizards and a few snakes, the occasional coyotes, bobcats, and rarely a deer.  This place feels ALIVE and I am home.

                                         Mom's place

                                         Aspens at Karr Canyon

                                         Historic downtown of Alamogordo

                                         Overlooking White Sands, NM

                                         Home looking west