A watershed moment: the future of mapping shallow,

sub-surface drainage tiles in Midwestern agricultural

watersheds using remote sensing.

Tim Deloriea

Questions addressed in this paper:

Why is there an interest in mapping the locations of drainage tiles?

Why are remote sensing and image interpretation techniques preferred over field investigations?

What have some past efforts in the area entailed? What can we learn from them?

What Methods will be used in future investigations?

clay drainage tiles

Tile Drainage

• lowers the water table

• increases yields

• farmers can plant earlier

• keeps crops from drowning

• Makes much of the farmland around here farm-able

Tile Drainage

• Midwest is EXTENSIVELY drained

• Many tile line locations are undocumented

• There is interest in detecting and mapping tile locations at the watershed scale--why?

Nutrient loading

Nutrient loading

Nutrient loadingNitrogen Cycle:

• consists of generally non-reactive N2

and biologically available nitrogen.

• microbial N fixation adds biologically available N to the nutrient cycle.

•  anthropogenic inputs are greatly increasing biologically available N.

Vitousek et. al. 1997

Nutrient loading

Vitousek et. al. 1997

Nutrient loadingEcosystem effects:

• N is often a limiting factor for biological production

• Many ecosystems are adapted to low levels of N

• Increases in available N can lead to subsequent decreases in biodiversity 

• Algal blooms, eutrophication, hypoxia

Vitousek et. al. 1997

Nutrient loadingHuman concerns:•  the United States EPA has set the Maximum Contaminant Level

(MCL) of of nitrate at 10 mg/L*

*I, however, remain skeptical of the ominous threats of "blue baby syndrome"

Nutrient loading

Where should we install wetlands?

Let's map the drainage tiles first!

How are we supposed to do that?

We should use remote sensing!

What sort of imagery can we use? isn't all of the free satellite imagery too coarse?

That's OK, I have some old aerial photographs around here somewhere!

Rules defined for the identification of potential tile‐drained fields using decision tree classification.

Mapping tile lines: Naz and Bowling (2008)

Steps followed to achieve the final maps used for comparisonwith known tile line map.

Mapping tile lines: Naz and Bowling (2008)

Basically, torture the poor image until it yields all of its dirty little secrets about hidden drainage tile.

Mapping tile lines: Naz and Bowling (2008)

Vector tile lines predicted from aerial images of 1976, 1998, and 2002 at Area 2. Regions 1, 2, and 3 indicate the areas where more of thetile lines are predicted for the year 1976, 1998, and 2002, respectively.

Ale, Naz, and Bowling, 2007

"it wasfound that only 6% of tile lines were identified from the 2002image and 3% from the 1998 image. In contrast, 71% of thesetile lines were identified in the 1976 image...

...as indicated by previous studies, the amount of rain eventshould be at least 25 mm two or three days before taking theaerial photograph"

From: Naz and Bowling, 2008How can we take our own pictures?

To catch a predator?

Precision Agriculture and Unmanned Aerial Vehicles (UAVs)

• UAVs may prove to be a cost effective way to gather data at the watershed scale--i.e. the agricultural drainage basin that empties into local surface water reservoirs.

Precision Agriculture and Unmanned Aerial Vehicles (UAVs)

• UAV exampleso http://aggieair.usu.edu/   Utah State Water Laboratoryo  http://www.autocopter.net/   AutoCopter 

conclusions:

• Midwestern agricultural stream ecosystems are stressed due to nutrient loading

• nutrient loading may be curtailed by the construction of wetlands—the decision of where to construct these wetlands may be influenced by the distribution of drainage tiles.

•  remote sensing techniques are useful for mapping tile drainage because they can be used to quickly and cheaply produce tile maps—but ideal images may not be available

• advances in UAV technology and affordability may provide an alternative to costly aerial imagery and provide potential for "real time" watershed management

Questions addressed in this paper:

Why is there an interest in mapping the locations of drainage tiles?

Why are remote sensing and image interpretation techniques preferred over field investigations?

What have some past efforts in this area entailed? What can we learn from them?

What Methods will be used in future investigations?

References:

Ale, S., Naz, B., and Bowling, L., 2007. Mapping of Tile Drains in Hoagland Watershed for Simulating the Effects of Drainage Water Management. ASABE Annual International Meeting Sponsored by ASABE, Minneapolis Convention Center, Minneapolis, Minnesota, 17-20 June 2007 Paper:072144.

Fewtrel, L., 2004. Drinking-Water Nitrate, Methemoglobinemia, and Global Burden of Disease: ADiscussion. Environmental Health Perspectives 112:1371-1374.

Kovacic, D.A., Twait, R.M., Wallace,M.P., Bowling, J.M., 2006. Use of created wetlands to improve water quality in the Midwest--Lake Bloomington case study. Ecological Engineering 28:258-270

Naz, B.S. and Bowling, L.C., 2008. Automated Identification of Tile Lines from Remotely Sensed Data. Transactions of the ASABE 51:1937-1950.Vitousek, P.M., Aber, J.D., Howarth, R.W., Likens, G.E., Matson,

P.A., Schindler, D.W., Schlesinger, W.H., and Tilman, D.G., 1997. Human alterations of the global nitrogen cycle: sources and consequences. Ecological Applications 7:737-750.

QUESTIONS?