The OP asks " ... how should I go about doing this." Your property appears to be rather flat. Coupled with close neighbors, things can get sticky. Start by getting someone other than yourself to document the existing grades over all of the project area. Use an engineer, surveyor, LA, or one who has many years of experience. The result should be a contour map with spot elevations also shown. The most important thing is the location where water is crossing the tract boundary. Before starting the design, study the drainage law of your area. Law differs from state to state, but the most common applicaton is the civil law doctrine of drainage. Here I repeat what I said on another thread. Note that part in bold. A good overview can be found at: http://publicworks.co.marion.or.us/engineering/DevEng/drainagelaw.asp "The lower owner must accept water which naturally comes to his land from above, ..." In Arizona: https://www.coconino.az.gov/uploadedFiles/Public_Works/Homeowner_Guide_To_Drainage.pdf "A second drainage law is "The Civil Law Rule of Natural rainage". This rule states that a landowner has the burden of receiving onto his/her land the surface water naturally falling onto and freely flowing onto it from land above it. The rule further states that a landowner has the right to have the surface water falling upon his/her land and naturally flowing onto it to flow freely from it onto lower parcels as it would flow under natural conditions. The key words are "naturally flowing". Any modifications to the surface topography or the drainage ways that cause natural flow to enter or leave a property differently (different peak flow elevations, frequencies and flow locations) can create a liability and put you at risk regarding litigation." Or from: http://web.aces.uiuc.edu/vista/pdf_pubs/DRAINAGE98.PDF "A landowner has no right to obstruct the flow of surface water. The owner of lower land obviously has no right to build a dam, levee, or other artificial structure that will interfere with the drainage of higher land, according to the CIVIL LAW as it is applied in Illinois."

With diligence, weeds can be successfully controlled under most conditions, but they will be easier to combat in a shady setting than one that is full sun. Since the stream is not distant, it would be pretty easy to establish shade that, with a high-pruned canopy, still allowed for a good view of the water. If this were mine, that's what I'd strive for. The minimum approach would include a tree canopy plus a durable groundcover. If you wanted to do more and have more interest, you could include shrubs, perennials and even some annuals. I would avoid fussy plants and use trees and groundcover that were easy to grow and not particular about soil or ones that needed soil amendments. Anything you plant will need fertilizer and supplemental watering. A vining groundcover would be the easiest to establish and it would cover objects--like rocks or stumps--sitting on top of the ground. You'd need to be especially diligent, until the groundcover and some shade was established, not to permit any weeds. If any were to re-seed or spread by roots, your job of getting rid of them would be greatly increased. You might need to be creative about mulch. Power company mulch would be good if you can get it. You might need to stabilize it (to keep from sliding down the hill) with sticks, branches and miscellaneous forest litter.

"Does this creek usually go dry in the summer? It seems to me with all the new leaves coming out, the trees and shrubs are absorbing more moisture than in the winter resulting in less flow in the creek." The creek dried up for about a week during last year's drought, but it hasn't dried up like that in the previous 60 years. In fact, it used to be much larger and wider. That does make sense about the trees & shrubs, but it has been going on since before the majority of trees & shrubs (chinese privet and tulip popular are most common) started leafing out/breaking dormancy. "I think your best bet IS to contact your local Soil and Water Conservation District. " They sent me an email this morning and I gave them some detailed information and the photos.

bellburgmaggie Thanks for putting that mockup together! Gives me a great idea of how beautiful I can make this look with some work. The tree and flowers you show on the opposite side of the creek is the neighbor's property, but there's still a lot I can do above the culverts and on our side. l pinkmountain I don't really know that a rain garden would slow the water through the culvert, as the other side of the culvert/uphill stream is across the street and not on our property. mad_gallica I suppose there could still be an obstruction, but it's only during seriously heavy torrential rains that we've seen it rise to the grass-line...during times when there's also flash flooding throughout the city. We have been here since late spring last year and I don't recall seeing anything of interest pop up along the water, but we will continue to keep an eye out. I have a friend who can come help me ID what trees are there and anything else we might have missed, but there doesn't seem to be much aside from the trees & vines. Thanks everyone for your help and advice. I came into this with the idea of doing some landscaping this spring, but you've all convinced me to use the spring and summer to clean things up and get ready for planting in the fall instead.